[Bug libstdc++/69744] New: OpenBSD does not define max_align_t

[edd at theunixzoo dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69744

            Bug ID: 69744
           Summary: OpenBSD does not define max_align_t
           Product: gcc
           Version: 4.9.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: edd at theunixzoo dot co.uk
  Target Milestone: ---

Hi,

I needed to build a "vanilla" (without all the packaging-related patches in
OpenBSD ports) gcc-4.9.3 on OpenBSD-5.8/amd64.

When building libstdc++ the build bombs out like this:

libtool: compile: 
/home/vext01/research/warmup_experiment/work/gcc/sd_build/./gcc/xgcc
-shared-libgcc
-B/home/vext01/research/warmup_experiment/work/gcc/sd_build/./gcc -nostdinc++
-L/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/src
-L/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/src/.libs
-L/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/libsupc++/.libs
-B/home/vext01/research/warmup_experiment/work/gcc-inst/x86_64-unknown-openbsd5.8/bin/
-B/home/vext01/research/warmup_experiment/work/gcc-inst/x86_64-unknown-openbsd5.8/lib/
-isystem
/home/vext01/research/warmup_experiment/work/gcc-inst/x86_64-unknown-openbsd5.8/include
-isystem
/home/vext01/research/warmup_experiment/work/gcc-inst/x86_64-unknown-openbsd5.8/sys-include
-I/home/vext01/research/warmup_experiment/work/gcc/libstdc++-v3/../libgcc
-I/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/x86_64-unknown-openbsd5.8
-I/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include
-I/home/vext01/research/warmup_experiment/work/gcc/libstdc++-v3/libsupc++
-D_GLIBCXX_SHARED -fno-implicit-templates -Wall -Wextra -Wwrite-strings
-Wcast-qual -Wabi -fdiagnostics-show-location=once -ffunction-sections
-fdata-sections -frandom-seed=eh_aux_runtime.lo -g -O2 -std=gnu++11 -c
../../../../libstdc++-v3/libsupc++/eh_aux_runtime.cc  -fPIC -DPIC
-D_GLIBCXX_SHARED -o eh_aux_runtime.o
In file included from ../../../../libstdc++-v3/libsupc++/unwind-cxx.h:35:0,
                 from ../../../../libstdc++-v3/libsupc++/eh_aux_runtime.cc:29:
/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/cstddef:51:11:
error: '::max_align_t' has not been declared
   using ::max_align_t;
           ^
Makefile:820: recipe for target 'eh_aux_runtime.lo' failed
gmake[5]: *** [eh_aux_runtime.lo] Error 1
gmake[5]: Leaving directory
'/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/libsupc++'


Having spoken to `redi' on IRC, it seems the problem is that OpenBSD's stddef.h
does not define max_align_t. Redi asked me to raise an issue.

Cheers