[PATCH v4 GCC 2/5] libffi/test: Fix compilation for build sysroot

["Maciej W. Rozycki" <macro@wdc.com>]

Fix a problem with the libffi testsuite using a method to determine the 
compiler to use resulting in the tool being different from one the 
library has been built with, and causing a catastrophic failure from the 
inability to actually choose any compiler at all in a cross-compilation 
configuration.

Address this problem by providing a DejaGNU configuration file defining 
the compiler to use, via the CC_FOR_TARGET TCL variable, set from $CC by 
autoconf, which will have all the required options set for the target 
compiler to build executables in the environment configured, removing 
failures like:

FAIL: libffi.call/closure_fn0.c -W -Wall -Wno-psabi -O0 (test for excess errors)
Excess errors:
default_target_compile: No compiler to compile with
UNRESOLVED: libffi.call/closure_fn0.c -W -Wall -Wno-psabi -O0 compilation failed to produce executable

and bringing overall test results for the `riscv64-linux-gnu' target 
(here with the `x86_64-linux-gnu' host and RISC-V QEMU in the Linux user 
emulation mode as the target board) from:

		=== libffi Summary ===

# of unexpected failures	708
# of unresolved testcases	708
# of unsupported tests		30

to:

		=== libffi Summary ===

# of expected passes		1934
# of unsupported tests		28

	libffi/
	* configure.ac: Add testsuite/local.exp to output files.
	* configure: Regenerate.
	* testsuite/local.exp.in: New file.
	* testsuite/Makefile.am (EXTRA_DEJAGNU_SITE_CONFIG): New 
	variable.
	* testsuite/Makefile.in: Regenerate.
---
This is a backport of upstream libffi change as recorded here: 
<https://sourceware.org/pipermail/libffi-discuss/2020/002503.html>.

New change in v4.
---
 libffi/configure              |    3 ++-
 libffi/configure.ac           |    2 +-
 libffi/testsuite/Makefile.am  |    2 ++
 libffi/testsuite/Makefile.in  |    5 ++++-
 libffi/testsuite/local.exp.in |    2 ++
 5 files changed, 11 insertions(+), 3 deletions(-)

gcc-test-libffi-cc-for-target-template.diff
Index: gcc/libffi/configure
===================================================================
--- gcc.orig/libffi/configure
+++ gcc/libffi/configure
@@ -16662,7 +16662,7 @@ ac_config_commands="$ac_config_commands
 ac_config_links="$ac_config_links include/ffitarget.h:src/$TARGETDIR/ffitarget.h"
 
 
-ac_config_files="$ac_config_files include/Makefile include/ffi.h Makefile testsuite/Makefile man/Makefile libffi.pc"
+ac_config_files="$ac_config_files include/Makefile include/ffi.h Makefile testsuite/Makefile testsuite/local.exp man/Makefile libffi.pc"
 
 
 cat >confcache <<\_ACEOF
@@ -17829,6 +17829,7 @@ do
     "include/ffi.h") CONFIG_FILES="$CONFIG_FILES include/ffi.h" ;;
     "Makefile") CONFIG_FILES="$CONFIG_FILES Makefile" ;;
     "testsuite/Makefile") CONFIG_FILES="$CONFIG_FILES testsuite/Makefile" ;;
+    "testsuite/local.exp") CONFIG_FILES="$CONFIG_FILES testsuite/local.exp" ;;
     "man/Makefile") CONFIG_FILES="$CONFIG_FILES man/Makefile" ;;
     "libffi.pc") CONFIG_FILES="$CONFIG_FILES libffi.pc" ;;
 
Index: gcc/libffi/configure.ac
===================================================================
--- gcc.orig/libffi/configure.ac
+++ gcc/libffi/configure.ac
@@ -377,6 +377,6 @@ test -d src/$TARGETDIR || mkdir src/$TAR
 
 AC_CONFIG_LINKS(include/ffitarget.h:src/$TARGETDIR/ffitarget.h)
 
-AC_CONFIG_FILES(include/Makefile include/ffi.h Makefile testsuite/Makefile man/Makefile libffi.pc)
+AC_CONFIG_FILES(include/Makefile include/ffi.h Makefile testsuite/Makefile testsuite/local.exp man/Makefile libffi.pc)
 
 AC_OUTPUT
Index: gcc/libffi/testsuite/Makefile.am
===================================================================
--- gcc.orig/libffi/testsuite/Makefile.am
+++ gcc/libffi/testsuite/Makefile.am
@@ -13,6 +13,8 @@ RUNTEST = `if [ -f $(top_srcdir)/../deja
 
 AM_RUNTESTFLAGS =
 
+EXTRA_DEJAGNU_SITE_CONFIG = local.exp
+
 CLEANFILES = *.exe core* *.log *.sum
 
 EXTRA_DIST = config/default.exp libffi.call/cls_19byte.c		\
Index: gcc/libffi/testsuite/Makefile.in
===================================================================
--- gcc.orig/libffi/testsuite/Makefile.in
+++ gcc/libffi/testsuite/Makefile.in
@@ -106,7 +106,7 @@ am__configure_deps = $(am__aclocal_m4_de
 DIST_COMMON = $(srcdir)/Makefile.am
 mkinstalldirs = $(SHELL) $(top_srcdir)/../mkinstalldirs
 CONFIG_HEADER = $(top_builddir)/fficonfig.h
-CONFIG_CLEAN_FILES =
+CONFIG_CLEAN_FILES = local.exp
 CONFIG_CLEAN_VPATH_FILES =
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
@@ -279,6 +279,7 @@ RUNTEST = `if [ -f $(top_srcdir)/../deja
 	       echo $(top_srcdir)/../dejagnu/runtest ; \
 	    else echo runtest; fi`
 
+EXTRA_DEJAGNU_SITE_CONFIG = local.exp
 CLEANFILES = *.exe core* *.log *.sum
 EXTRA_DIST = config/default.exp libffi.call/cls_19byte.c		\
 libffi.call/cls_align_longdouble_split.c				\
@@ -390,6 +391,8 @@ $(top_srcdir)/configure: @MAINTAINER_MOD
 $(ACLOCAL_M4): @MAINTAINER_MODE_TRUE@ $(am__aclocal_m4_deps)
 	cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh
 $(am__aclocal_m4_deps):
+local.exp: $(top_builddir)/config.status $(srcdir)/local.exp.in
+	cd $(top_builddir) && $(SHELL) ./config.status $(subdir)/$@
 
 mostlyclean-libtool:
 	-rm -f *.lo
Index: gcc/libffi/testsuite/local.exp.in
===================================================================
--- /dev/null
+++ gcc/libffi/testsuite/local.exp.in
@@ -0,0 +1,2 @@
+set CC_FOR_TARGET "@CC@"
+set CXX_FOR_TARGET "@CXX@"