I tried compiling version 12.2.0 and it attempts to access system headers
at /usr/include, but on mac the system headers are stored at

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include.

Here's my error:
rm -rf include-fixed; mkdir include-fixed
chmod a+rx include-fixed
if [ -d ../prev-gcc ]; then \
	  cd ../prev-gcc && \
	  /Library/Developer/CommandLineTools/usr/bin/make
real-install-headers-tar DESTDIR=`pwd`/../gcc/ \
	    libsubdir=. ; \
	else \
	  set -e; for ml in `cat fixinc_list`; do \
	    sysroot_headers_suffix=`echo ${ml} | sed -e 's/;.*$//'`; \
	    multi_dir=`echo ${ml} | sed -e 's/^[^;]*;//'`; \
	    fix_dir=include-fixed${multi_dir}; \
	    if ! false && test ! -d `echo /usr/include | sed -e :a -e
's,[^/]*/\.\.\/,,' -e ta`; then \
	      echo The directory that should contain system headers does not
exist: >&2 ; \
	      echo "  `echo /usr/include | sed -e :a -e 's,[^/]*/\.\.\/,,' -e
ta`" >&2 ; \
	      tooldir_sysinc=`echo
"/lib/gcc/x86_64-apple-darwin21.6.0/12.2.0/../../../../x86_64-apple-darwin21.6.0/sys-include"
| sed -e :a -e "s,[^/]*/\.\.\/,," -e ta`; \
	      if test "x`echo /usr/include | sed -e :a -e 's,[^/]*/\.\.\/,,'
-e ta`" = "x${tooldir_sysinc}"; \
	      then sleep 1; else exit 1; fi; \
	    fi; \
	    /bin/sh ../../gcc-12.2.0/gcc/../mkinstalldirs ${fix_dir}; \
	    chmod a+rx ${fix_dir} || true; \
	    (TARGET_MACHINE='x86_64-apple-darwin21.6.0'; srcdir=`cd
../../gcc-12.2.0/gcc; ${PWDCMD-pwd}`; \
	      SHELL='/bin/sh'; MACRO_LIST=`${PWDCMD-pwd}`/macro_list ; \
	      gcc_dir=`${PWDCMD-pwd}` ; \
	      export TARGET_MACHINE srcdir SHELL MACRO_LIST && \
	      cd ../build-x86_64-apple-darwin21.6.0/fixincludes && \
	      /bin/sh ./fixinc.sh "${gcc_dir}/${fix_dir}" \
	        `echo /usr/include | sed -e :a -e 's,[^/]*/\.\.\/,,' -e ta`  ); \
	    rm -f ${fix_dir}/syslimits.h; \
	    if [ -f ${fix_dir}/limits.h ]; then \
	      mv ${fix_dir}/limits.h ${fix_dir}/syslimits.h; \
	    else \
	      cp ../../gcc-12.2.0/gcc/gsyslimits.h ${fix_dir}/syslimits.h; \
	    fi; \
	    chmod a+r ${fix_dir}/syslimits.h; \
	  done; \
	fi
The directory that should contain system headers does not exist:
  /usr/include
make[1]: *** [stmp-fixinc] Error 1
make: *** [all-gcc] Error 2


On Fri, Feb 17, 2023 at 8:04 AM Iain Sandoe <idsandoe@googlemail.com> wrote:

>
>
> > On 17 Feb 2023, at 15:37, Jonathan Wakely via Gcc <gcc@gcc.gnu.org>
> wrote:
> >
> > On Fri, 17 Feb 2023, 15:17 -xlan- via Gcc, <gcc@gcc.gnu.org> wrote:
> >
> >> I was building gcc version 4.9.1
> >
> >
> > Why?
>
> Indeed, what is the use-case?
> trying to build such an old GCC version on modern macOS could be
> problematic.
>
> > on Mac OS version when I got this error:
> >>
> >> In file included from ../../gcc-4.9.1/gcc/c/c-objc-common.c:33:
> >> In file included from
> >>
> >>
> /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1/new:93:
> >>
> >>
> /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/v1/exception:184:5:
> >> error: no member named 'fancy_abort' in namespace 'std::__1'; did you
> mean
> >> simply 'fancy_abort'?
> >>    _VSTD::abort();
> >>    ^~~~~~~
> >>
> >
> >
> > The GCC sources define 'abort' as a macro, which appears to be
> incompatible
> > with LLVM's libc++.
> >
> > You might be able to compile using -stdlib=libstdc++ instead.
>
> There are no headers for libstdc++ in SDKs for OSX 10.13 + (so you would
> need also to find an
> older SDK and then build with an OSX target of say 10.12).
>
> What you are trying to do is going to required quite advanced techniques
> to deal with the difference in the OS, compiler and bootstrap tools.  I
> have not attempted anything < GCC-5 on newer machines.
>
> Iain
>
>
>
>