On Mon, 15 Oct 2018 at 10:12, Christophe Lyon
<christophe.lyon@linaro.org> wrote:
>
>
>
> On Fri, 12 Oct 2018 at 11:54, Richard Earnshaw (lists) <Richard.Earnshaw@arm.com> wrote:
>>
>> On 11/10/18 14:34, Christophe Lyon wrote:
>> > The new arm-uclinuxfdpiceabi target behaves pretty much like
>> > arm-linux-gnueabi. In order the enable the same set of features, we
>> > have to update several configure scripts that generally match targets
>> > like *-*-linux*: in most places, we add *-uclinux* where there is
>> > already *-linux*, or uclinux* when there is already linux*.
>> >
>> > In gcc/config.gcc and libgcc/config.host we use *-*-uclinuxfdpiceabi
>> > because there is already a different behaviour for *-*uclinux* target.
>> >
>> > In libtool.m4, we use uclinuxfdpiceabi in cases where ELF shared
>> > libraries support is required, as uclinux does not guarantee that.
>> >
>> > 2018-XX-XX  Christophe Lyon  <christophe.lyon@st.com>
>> >
>> >       config/
>> >       * futex.m4: Handle *-uclinux*.
>> >       * tls.m4 (GCC_CHECK_TLS): Likewise.
>> >
>> >       gcc/
>> >       * config.gcc: Handle *-*-uclinuxfdpiceabi.
>> >
>> >       libatomic/
>> >       * configure.tgt: Handle arm*-*-uclinux*.
>> >       * configure: Regenerate.
>> >
>> >       libgcc/
>> >       * config.host: Handle *-*-uclinuxfdpiceabi.
>> >
>> >       libitm/
>> >       * configure.tgt: Handle *-*-uclinux*.
>> >       * configure: Regenerate.
>> >
>> >       libstdc++-v3/
>> >       * acinclude.m4: Handle uclinux*.
>> >       * configure: Regenerate.
>> >       * configure.host: Handle uclinux*
>> >
>> >       * libtool.m4: Handle uclinux*.
>>
>> What testing have you done to ensure that these new uclinux* changes
>> have not affected existing uclinux configurations?
>>
>> Also, do you really need to use uclinuxfdpiceabi (which is quite
>> Arm-specific) everywhere, or would uclinuxfdpic* be better and ease work
>> for other fdpic targets?
>>

Thanks to the help I received in
https://gcc.gnu.org/ml/gcc/2018-10/msg00154.html
https://gcc.gnu.org/ml/gcc/2018-11/msg00012.html
I managed to build an xtensa-buildroot-uclinux-uclibc toolchain
(r265582), and run 'make check'.
Then I applied this patch, rebuilt the toolchain (from scratch) and
ran 'make check' again.
compare_test says:
Tests that now fail, but worked before (54 tests):
[...]
Tests that now work, but didn't before (2 tests):
23_containers/map/requirements/exception/propagation_consistent.cc
execution test
ext/mt_allocator/deallocate_global_thread-3.cc execution test

New tests that FAIL (4 tests):
27_io/filesystem/path/native/string.cc (test for excess errors)
30_threads/condition_variable_any/50862.cc execution test
30_threads/condition_variable_any/53830.cc execution test
experimental/filesystem/path/native/string.cc (test for excess errors)

New tests that PASS (301 tests):
[...]

(all the diffs are in libstdc++ obviously)
I've attached the details to this email.

>
> This patch became necessary when I was asked to change the target name from  arm-linux-uclibceabi to arm-uclinuxfdpiceabi.
> Changing it implied that many features were disabled and tests regressed because the new target name didn't match the regexps in configure scripts.
>
> I iterated over the regressions to see which features were now missing, and I updated the configure scripts accordingly.
>
> When the feature being tested was generic, I used the general *-*-uclinux* form, because it seemed reasonable that it was OK for other targets.
> When the test was arm-related, I used the stricter uclinuxfdpiceabi form, and specifically not uclinuxfdpic* to avoid breaking other fdpic targets. When in doubt, I preferred to stay on the safe side.
>
> To answer you first question, I do not have the setup to test other uclinux configs, I'm not even sure of the list.
> So I tested arm-uclinuxfdpiceabi, made sure I got the same results as with our previous target name, and that
> the whole series didn't regress on arm-linux-gnueabi*.
>
> I hope other uclinux/fdpic target maintainers comment on this patch if something looks wrong to them.
>
> Christophe
>
>> R.
>> >
>> > Change-Id: I6a1fdcd9847d8a82179a214612a3474c1f492916
>> >
>> > diff --git a/config/futex.m4 b/config/futex.m4
>> > index e95144d..4dffe15 100644
>> > --- a/config/futex.m4
>> > +++ b/config/futex.m4
>> > @@ -9,7 +9,7 @@ AC_DEFUN([GCC_LINUX_FUTEX],[dnl
>> >  GCC_ENABLE(linux-futex,default, ,[use the Linux futex system call],
>> >          permit yes|no|default)
>> >  case "$target" in
>> > -  *-linux*)
>> > +  *-linux* | *-uclinux*)
>> >      case "$enable_linux_futex" in
>> >        default)
>> >       # If headers don't have gettid/futex syscalls definition, then
>> > diff --git a/config/tls.m4 b/config/tls.m4
>> > index 4e170c8..5a8676e 100644
>> > --- a/config/tls.m4
>> > +++ b/config/tls.m4
>> > @@ -76,7 +76,7 @@ AC_DEFUN([GCC_CHECK_TLS], [
>> >         dnl Shared library options may depend on the host; this check
>> >         dnl is only known to be needed for GNU/Linux.
>> >         case $host in
>> > -         *-*-linux*)
>> > +         *-*-linux* | -*-uclinux*)
>> >             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
>> >             ;;
>> >         esac
>> > diff --git a/gcc/config.gcc b/gcc/config.gcc
>> > index 0c579d1..793fc69 100644
>> > --- a/gcc/config.gcc
>> > +++ b/gcc/config.gcc
>> > @@ -753,7 +753,7 @@ case ${target} in
>> >  *-*-fuchsia*)
>> >    native_system_header_dir=/include
>> >    ;;
>> > -*-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu)
>> > +*-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu | *-*-uclinuxfdpiceabi)
>> >    extra_options="$extra_options gnu-user.opt"
>> >    gas=yes
>> >    gnu_ld=yes
>> > @@ -762,7 +762,7 @@ case ${target} in
>> >    esac
>> >    tmake_file="t-slibgcc"
>> >    case $target in
>> > -    *-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-kopensolaris*-gnu)
>> > +    *-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-kopensolaris*-gnu  | *-*-uclinuxfdpiceabi)
>> >        :;;
>> >      *-*-gnu*)
>> >        native_system_header_dir=/include
>> > @@ -782,7 +782,7 @@ case ${target} in
>> >      *-*-*android*)
>> >        tm_defines="$tm_defines DEFAULT_LIBC=LIBC_BIONIC"
>> >        ;;
>> > -    *-*-*uclibc*)
>> > +    *-*-*uclibc* | *-*-uclinuxfdpiceabi)
>> >        tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
>> >        ;;
>> >      *-*-*musl*)
>> > @@ -1134,7 +1134,7 @@ arm*-*-netbsdelf*)
>> >       tmake_file="${tmake_file} arm/t-arm"
>> >       target_cpu_cname="arm6"
>> >       ;;
>> > -arm*-*-linux-*)                      # ARM GNU/Linux with ELF
>> > +arm*-*-linux-* | arm*-*-uclinuxfdpiceabi)                    # ARM GNU/Linux with ELF
>> >       tm_file="dbxelf.h elfos.h gnu-user.h linux.h linux-android.h glibc-stdint.h arm/elf.h arm/linux-gas.h arm/linux-elf.h"
>> >       extra_options="${extra_options} linux-android.opt"
>> >       case $target in
>> > diff --git a/libatomic/configure b/libatomic/configure
>> > index b902e2c..5b3ef8e 100755
>> > --- a/libatomic/configure
>> > +++ b/libatomic/configure
>> > @@ -5819,7 +5819,7 @@ irix5* | irix6* | nonstopux*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    lt_cv_deplibs_check_method=pass_all
>> >    ;;
>> >
>> > @@ -8305,7 +8305,7 @@ $as_echo_n "checking for $compiler option to produce PIC... " >&6; }
>> >        lt_prog_compiler_static='-non_shared'
>> >        ;;
>> >
>> > -    linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >        case $cc_basename in
>> >        # old Intel for x86_64 which still supported -KPIC.
>> >        ecc*)
>> > @@ -8900,7 +8900,7 @@ _LT_EOF
>> >        archive_expsym_cmds='sed "s,^,_," $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags ${wl}-h,$soname ${wl}--retain-symbols-file,$output_objdir/$soname.expsym ${wl}--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
>> >        ;;
>> >
>> > -    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >        tmp_diet=no
>> >        if test "$host_os" = linux-dietlibc; then
>> >       case $cc_basename in
>> > @@ -10431,7 +10431,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > diff --git a/libatomic/configure.tgt b/libatomic/configure.tgt
>> > index ea8c34f..c1a608f 100644
>> > --- a/libatomic/configure.tgt
>> > +++ b/libatomic/configure.tgt
>> > @@ -124,7 +124,7 @@ case "${target}" in
>> >       config_path="${config_path} linux/aarch64 posix"
>> >       ;;
>> >
>> > -  arm*-*-linux*)
>> > +  arm*-*-linux* | arm*-*-uclinux*)
>> >       # OS support for atomic primitives.
>> >       config_path="${config_path} linux/arm posix"
>> >       ;;
>> > diff --git a/libgcc/config.host b/libgcc/config.host
>> > index 029f656..28f3c14 100644
>> > --- a/libgcc/config.host
>> > +++ b/libgcc/config.host
>> > @@ -238,7 +238,7 @@ case ${host} in
>> >    tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip t-slibgcc t-slibgcc-fuchsia"
>> >    extra_parts="crtbegin.o crtend.o"
>> >    ;;
>> > -*-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu)
>> > +*-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu | *-*-uclinuxfdpiceabi)
>> >    tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver t-linux"
>> >    extra_parts="crtbegin.o crtbeginS.o crtbeginT.o crtend.o crtendS.o"
>> >    if test x$enable_vtable_verify = xyes; then
>> > @@ -424,7 +424,7 @@ arm*-*-fuchsia*)
>> >  arm*-*-netbsdelf*)
>> >       tmake_file="$tmake_file arm/t-arm arm/t-netbsd t-slibgcc-gld-nover"
>> >       ;;
>> > -arm*-*-linux*)                       # ARM GNU/Linux with ELF
>> > +arm*-*-linux* | arm*-*-uclinuxfdpiceabi)                     # ARM GNU/Linux with ELF
>> >       tmake_file="${tmake_file} arm/t-arm t-fixedpoint-gnu-prefix t-crtfm"
>> >       tmake_file="${tmake_file} arm/t-elf arm/t-bpabi arm/t-linux-eabi t-slibgcc-libgcc"
>> >       tm_file="$tm_file arm/bpabi-lib.h"
>> > diff --git a/libitm/configure b/libitm/configure
>> > index dbf386d..fd82500 100644
>> > --- a/libitm/configure
>> > +++ b/libitm/configure
>> > @@ -6494,7 +6494,7 @@ irix5* | irix6* | nonstopux*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    lt_cv_deplibs_check_method=pass_all
>> >    ;;
>> >
>> > @@ -8981,7 +8981,7 @@ $as_echo_n "checking for $compiler option to produce PIC... " >&6; }
>> >        lt_prog_compiler_static='-non_shared'
>> >        ;;
>> >
>> > -    linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >        case $cc_basename in
>> >        # old Intel for x86_64 which still supported -KPIC.
>> >        ecc*)
>> > @@ -9576,7 +9576,7 @@ _LT_EOF
>> >        archive_expsym_cmds='sed "s,^,_," $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags ${wl}-h,$soname ${wl}--retain-symbols-file,$output_objdir/$soname.expsym ${wl}--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
>> >        ;;
>> >
>> > -    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >        tmp_diet=no
>> >        if test "$host_os" = linux-dietlibc; then
>> >       case $cc_basename in
>> > @@ -11107,7 +11107,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > @@ -13008,7 +13008,7 @@ if test -z "$aix_libpath"; then aix_libpath="/usr/lib:/lib"; fi
>> >          inherit_rpath_CXX=yes
>> >          ;;
>> >
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >          case $cc_basename in
>> >            KCC*)
>> >           # Kuck and Associates, Inc. (KAI) C++ Compiler
>> > @@ -13595,7 +13595,7 @@ interix[3-9]*)
>> >    postdeps_CXX=
>> >    ;;
>> >
>> > -linux*)
>> > +linux* | uclinux*)
>> >    case `$CC -V 2>&1 | sed 5q` in
>> >    *Sun\ C*)
>> >      # Sun C++ 5.9
>> > @@ -13846,7 +13846,7 @@ $as_echo_n "checking for $compiler option to produce PIC... " >&6; }
>> >           ;;
>> >       esac
>> >       ;;
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >       case $cc_basename in
>> >         KCC*)
>> >           # KAI C++ Compiler
>> > @@ -14767,7 +14767,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > @@ -16239,7 +16239,7 @@ fi
>> >
>> >
>> >  case "$target" in
>> > -  *-linux*)
>> > +  *-linux* | *-uclinux*)
>> >      case "$enable_linux_futex" in
>> >        default)
>> >       # If headers don't have gettid/futex syscalls definition, then
>> > @@ -16362,7 +16362,7 @@ _ACEOF
>> >  if ac_fn_c_try_link "$LINENO"; then :
>> >    chktls_save_LDFLAGS="$LDFLAGS"
>> >                         case $host in
>> > -         *-*-linux*)
>> > +         *-*-linux* | -*-uclinux*)
>> >             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
>> >             ;;
>> >         esac
>> > diff --git a/libitm/configure.tgt b/libitm/configure.tgt
>> > index 0cbb097..bc6c3ca 100644
>> > --- a/libitm/configure.tgt
>> > +++ b/libitm/configure.tgt
>> > @@ -127,7 +127,7 @@ config_path="$ARCH posix generic"
>> >
>> >  # Other system configury
>> >  case "${target}" in
>> > -  *-*-linux*)
>> > +  *-*-linux* | *-*-uclinux*)
>> >       if test "$enable_linux_futex" = yes; then
>> >         config_path="linux/$ARCH linux $config_path"
>> >       fi
>> > diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
>> > index 6d68e90..2e18049 100644
>> > --- a/libstdc++-v3/acinclude.m4
>> > +++ b/libstdc++-v3/acinclude.m4
>> > @@ -1395,7 +1395,7 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [
>> >          ac_has_nanosleep=yes
>> >          ac_has_sched_yield=yes
>> >          ;;
>> > -      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >          AC_MSG_CHECKING([for at least GNU libc 2.17])
>> >          AC_TRY_COMPILE(
>> >            [#include <features.h>],
>> > @@ -1517,7 +1517,7 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [
>> >
>> >    if test x"$ac_has_clock_monotonic" != x"yes"; then
>> >      case ${target_os} in
>> > -      linux*)
>> > +      linux* | uclinux*)
>> >       AC_MSG_CHECKING([for clock_gettime syscall])
>> >       AC_TRY_COMPILE(
>> >         [#include <unistd.h>
>> > @@ -2402,7 +2402,7 @@ AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
>> >    # Default to "generic".
>> >    if test $enable_clocale_flag = auto; then
>> >      case ${target_os} in
>> > -      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >       enable_clocale_flag=gnu
>> >       ;;
>> >        darwin*)
>> > @@ -2648,7 +2648,7 @@ AC_DEFUN([GLIBCXX_ENABLE_ALLOCATOR], [
>> >    # Default to "new".
>> >    if test $enable_libstdcxx_allocator_flag = auto; then
>> >      case ${target_os} in
>> > -      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >       enable_libstdcxx_allocator_flag=new
>> >       ;;
>> >        *)
>> > @@ -4282,7 +4282,7 @@ AC_DEFUN([GLIBCXX_ENABLE_FILESYSTEM_TS], [
>> >        freebsd*|netbsd*|openbsd*|dragonfly*|darwin*)
>> >          enable_libstdcxx_filesystem_ts=yes
>> >          ;;
>> > -      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >          enable_libstdcxx_filesystem_ts=yes
>> >          ;;
>> >        rtems*)
>> > @@ -4430,7 +4430,7 @@ dnl
>> >      AC_MSG_CHECKING([for sendfile that can copy files])
>> >      AC_CACHE_VAL(glibcxx_cv_sendfile, [dnl
>> >        case "${target_os}" in
>> > -        gnu* | linux* | solaris*)
>> > +        gnu* | linux* | solaris* | uclinux*)
>> >            GCC_TRY_COMPILE_OR_LINK(
>> >              [#include <sys/sendfile.h>],
>> >              [sendfile(1, 2, (off_t*)0, sizeof 1);],
>> > diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
>> > index d33081d..7780679 100755
>> > --- a/libstdc++-v3/configure
>> > +++ b/libstdc++-v3/configure
>> > @@ -6413,7 +6413,7 @@ irix5* | irix6* | nonstopux*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    lt_cv_deplibs_check_method=pass_all
>> >    ;;
>> >
>> > @@ -8765,7 +8765,7 @@ $as_echo_n "checking for $compiler option to produce PIC... " >&6; }
>> >        lt_prog_compiler_static='-non_shared'
>> >        ;;
>> >
>> > -    linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >        case $cc_basename in
>> >        # old Intel for x86_64 which still supported -KPIC.
>> >        ecc*)
>> > @@ -9360,7 +9360,7 @@ _LT_EOF
>> >        archive_expsym_cmds='sed "s,^,_," $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags ${wl}-h,$soname ${wl}--retain-symbols-file,$output_objdir/$soname.expsym ${wl}--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
>> >        ;;
>> >
>> > -    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >        tmp_diet=no
>> >        if test "$host_os" = linux-dietlibc; then
>> >       case $cc_basename in
>> > @@ -10900,7 +10900,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > @@ -12825,7 +12825,7 @@ if test -z "$aix_libpath"; then aix_libpath="/usr/lib:/lib"; fi
>> >          inherit_rpath_CXX=yes
>> >          ;;
>> >
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >          case $cc_basename in
>> >            KCC*)
>> >           # Kuck and Associates, Inc. (KAI) C++ Compiler
>> > @@ -13412,7 +13412,7 @@ interix[3-9]*)
>> >    postdeps_CXX=
>> >    ;;
>> >
>> > -linux*)
>> > +linux* | uclinux*)
>> >    case `$CC -V 2>&1 | sed 5q` in
>> >    *Sun\ C*)
>> >      # Sun C++ 5.9
>> > @@ -13663,7 +13663,7 @@ $as_echo_n "checking for $compiler option to produce PIC... " >&6; }
>> >           ;;
>> >       esac
>> >       ;;
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >       case $cc_basename in
>> >         KCC*)
>> >           # KAI C++ Compiler
>> > @@ -14584,7 +14584,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > @@ -15833,7 +15833,7 @@ fi
>> >    # Default to "generic".
>> >    if test $enable_clocale_flag = auto; then
>> >      case ${target_os} in
>> > -      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >       enable_clocale_flag=gnu
>> >       ;;
>> >        darwin*)
>> > @@ -16250,7 +16250,7 @@ fi
>> >    # Default to "new".
>> >    if test $enable_libstdcxx_allocator_flag = auto; then
>> >      case ${target_os} in
>> > -      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >       enable_libstdcxx_allocator_flag=new
>> >       ;;
>> >        *)
>> > @@ -20526,7 +20526,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
>> >          ac_has_nanosleep=yes
>> >          ac_has_sched_yield=yes
>> >          ;;
>> > -      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >          { $as_echo "$as_me:${as_lineno-$LINENO}: checking for at least GNU libc 2.17" >&5
>> >  $as_echo_n "checking for at least GNU libc 2.17... " >&6; }
>> >          cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>> > @@ -21026,7 +21026,7 @@ $as_echo "$ac_has_nanosleep" >&6; }
>> >
>> >    if test x"$ac_has_clock_monotonic" != x"yes"; then
>> >      case ${target_os} in
>> > -      linux*)
>> > +      linux* | uclinux*)
>> >       { $as_echo "$as_me:${as_lineno-$LINENO}: checking for clock_gettime syscall" >&5
>> >  $as_echo_n "checking for clock_gettime syscall... " >&6; }
>> >       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>> > @@ -27918,7 +27918,7 @@ _ACEOF
>> >  if ac_fn_c_try_link "$LINENO"; then :
>> >    chktls_save_LDFLAGS="$LDFLAGS"
>> >                         case $host in
>> > -         *-*-linux*)
>> > +         *-*-linux* | -*-uclinux*)
>> >             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
>> >             ;;
>> >         esac
>> > @@ -53578,7 +53578,7 @@ _ACEOF
>> >  if ac_fn_c_try_link "$LINENO"; then :
>> >    chktls_save_LDFLAGS="$LDFLAGS"
>> >                         case $host in
>> > -         *-*-linux*)
>> > +         *-*-linux* | -*-uclinux*)
>> >             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
>> >             ;;
>> >         esac
>> > @@ -59771,7 +59771,7 @@ _ACEOF
>> >  if ac_fn_c_try_link "$LINENO"; then :
>> >    chktls_save_LDFLAGS="$LDFLAGS"
>> >                         case $host in
>> > -         *-*-linux*)
>> > +         *-*-linux* | -*-uclinux*)
>> >             LDFLAGS="-shared -Wl,--no-undefined $LDFLAGS"
>> >             ;;
>> >         esac
>> > @@ -78397,7 +78397,7 @@ fi
>> >
>> >
>> >  case "$target" in
>> > -  *-linux*)
>> > +  *-linux* | *-uclinux*)
>> >      case "$enable_linux_futex" in
>> >        default)
>> >       # If headers don't have gettid/futex syscalls definition, then
>> > @@ -80033,7 +80033,7 @@ $as_echo_n "checking whether to build Filesystem TS support... " >&6; }
>> >        freebsd*|netbsd*|openbsd*|dragonfly*|darwin*)
>> >          enable_libstdcxx_filesystem_ts=yes
>> >          ;;
>> > -      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
>> > +      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
>> >          enable_libstdcxx_filesystem_ts=yes
>> >          ;;
>> >        rtems*)
>> > @@ -80457,7 +80457,7 @@ $as_echo_n "checking for sendfile that can copy files... " >&6; }
>> >    $as_echo_n "(cached) " >&6
>> >  else
>> >          case "${target_os}" in
>> > -        gnu* | linux* | solaris*)
>> > +        gnu* | linux* | solaris* | uclinux*)
>> >            if test x$gcc_no_link = xyes; then
>> >    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>> >  /* end confdefs.h.  */
>> > diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
>> > index 155a3cd..1c298ab 100644
>> > --- a/libstdc++-v3/configure.host
>> > +++ b/libstdc++-v3/configure.host
>> > @@ -264,7 +264,7 @@ case "${host_os}" in
>> >    linux-musl*)
>> >      os_include_dir="os/generic"
>> >      ;;
>> > -  gnu* | linux* | kfreebsd*-gnu)
>> > +  gnu* | linux* | kfreebsd*-gnu | uclinux*)
>> >      if [ "$uclibc" = "yes" ]; then
>> >        os_include_dir="os/uclibc"
>> >      elif [ "$bionic" = "yes" ]; then
>> > @@ -327,7 +327,7 @@ esac
>> >  # Set any OS-dependent and CPU-dependent bits.
>> >  # THIS TABLE IS SORTED.  KEEP IT THAT WAY.
>> >  case "${host}" in
>> > -  *-*-linux*)
>> > +  *-*-linux* | *-*-uclinux*)
>> >      case "${host_cpu}" in
>> >        i[567]86)
>> >          abi_baseline_pair=i486-linux-gnu
>> > @@ -358,7 +358,7 @@ case "${host}" in
>> >          fi
>> >      esac
>> >      case "${host}" in
>> > -      arm*-*-linux-*)
>> > +      arm*-*-linux-* | arm*-*-uclinuxfdpiceabi)
>> >       port_specific_symbol_files="\$(srcdir)/../config/os/gnu-linux/arm-eabi-extra.ver"
>> >       ;;
>> >      esac
>> > diff --git a/libtool.m4 b/libtool.m4
>> > index 940faaa..49ab293 100644
>> > --- a/libtool.m4
>> > +++ b/libtool.m4
>> > @@ -2449,7 +2449,7 @@ linux*oldld* | linux*aout* | linux*coff*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    version_type=linux
>> >    need_lib_prefix=no
>> >    need_version=no
>> > @@ -3089,7 +3089,7 @@ irix5* | irix6* | nonstopux*)
>> >    ;;
>> >
>> >  # This must be Linux ELF.
>> > -linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >    lt_cv_deplibs_check_method=pass_all
>> >    ;;
>> >
>> > @@ -3734,7 +3734,7 @@ m4_if([$1], [CXX], [
>> >           ;;
>> >       esac
>> >       ;;
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >       case $cc_basename in
>> >         KCC*)
>> >           # KAI C++ Compiler
>> > @@ -4032,7 +4032,7 @@ m4_if([$1], [CXX], [
>> >        _LT_TAGVAR(lt_prog_compiler_static, $1)='-non_shared'
>> >        ;;
>> >
>> > -    linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinux*)
>> >        case $cc_basename in
>> >        # old Intel for x86_64 which still supported -KPIC.
>> >        ecc*)
>> > @@ -4449,7 +4449,7 @@ _LT_EOF
>> >        _LT_TAGVAR(archive_expsym_cmds, $1)='sed "s,^,_," $export_symbols >$output_objdir/$soname.expsym~$CC -shared $pic_flag $libobjs $deplibs $compiler_flags ${wl}-h,$soname ${wl}--retain-symbols-file,$output_objdir/$soname.expsym ${wl}--image-base,`expr ${RANDOM-$$} % 4096 / 2 \* 262144 + 1342177280` -o $lib'
>> >        ;;
>> >
>> > -    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >        tmp_diet=no
>> >        if test "$host_os" = linux-dietlibc; then
>> >       case $cc_basename in
>> > @@ -5946,7 +5946,7 @@ if test "$_lt_caught_CXX_error" != yes; then
>> >          _LT_TAGVAR(inherit_rpath, $1)=yes
>> >          ;;
>> >
>> > -      linux* | k*bsd*-gnu | kopensolaris*-gnu)
>> > +      linux* | k*bsd*-gnu | kopensolaris*-gnu | uclinuxfdpiceabi)
>> >          case $cc_basename in
>> >            KCC*)
>> >           # Kuck and Associates, Inc. (KAI) C++ Compiler
>> > @@ -6598,7 +6598,7 @@ interix[[3-9]]*)
>> >    _LT_TAGVAR(postdeps,$1)=
>> >    ;;
>> >
>> > -linux*)
>> > +linux* | uclinux*)
>> >    case `$CC -V 2>&1 | sed 5q` in
>> >    *Sun\ C*)
>> >      # Sun C++ 5.9
>> >
>>