[Bug bootstrap/70650] New: bootstrap failure on x86_64 darwin

["howarth.at.gcc at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70650

            Bug ID: 70650
           Summary: bootstrap failure on x86_64 darwin
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: howarth.at.gcc at gmail dot com
  Target Milestone: ---

At r234969, the bootstrap of x86_64-apple-darwin15 fails with...

libtool: compile:  /sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/./gcc/xgcc
-shared-libgcc -B/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/./gcc
-nostdinc++
-L/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src
-L/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src/.libs
-L/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/libsupc++/.libs
-B/sw/lib/gcc6/x86_64-apple-darwin15.5.0/bin/
-B/sw/lib/gcc6/x86_64-apple-darwin15.5.0/lib/ -isystem
/sw/lib/gcc6/x86_64-apple-darwin15.5.0/include -isystem
/sw/lib/gcc6/x86_64-apple-darwin15.5.0/sys-include
-I/sw/src/fink.build/gcc6-6.0.0-1/gcc-6-20160413/libstdc++-v3/../libgcc
-I/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/include/x86_64-apple-darwin15.5.0
-I/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/include
-I/sw/src/fink.build/gcc6-6.0.0-1/gcc-6-20160413/libstdc++-v3/libsupc++
-I/sw/include -I/sw/include -std=gnu++11 -D_GLIBCXX_SHARED
-fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi
-fdiagnostics-show-location=once -fvisibility-inlines-hidden
-ffunction-sections -fdata-sections -frandom-seed=string-inst.lo -g -O2 -c
../../../../../gcc-6-20160413/libstdc++-v3/src/c++11/string-inst.cc 
-fno-common -DPIC -D_GLIBCXX_SHARED -o string-inst.o
In file included from
/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/include/string:53:0,
                 from
../../../../../gcc-6-20160413/libstdc++-v3/src/c++11/string-inst.cc:38:
/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/include/bits/basic_string.tcc:
In member function âvoid std::__cxx11::basic_string<_CharT, _Traits,
_Alloc>::_M_construct(_InIterator, _InIterator, std::forward_iterator_tag)
[with _FwdIterator = char*; _CharT = char; _Traits = std::char_traits<char>;
_Alloc = std::allocator<char>]â:
/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/include/bits/basic_string.tcc:206:7:
internal compiler error: in emit_move_insn, at expr.c:3546
       basic_string<_CharT, _Traits, _Alloc>::
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libbacktrace could not find executable to open
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
Makefile:545: recipe for target 'string-inst.lo' failed
make[6]: *** [string-inst.lo] Error 1
make[6]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src/c++11'
Making all in filesystem
make[6]: Entering directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src/filesystem'
make[6]: Nothing to be done for 'all'.
make[6]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src/filesystem'
make[6]: Entering directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src'
make[6]: *** No rule to make target '../src/c++11/libc++11convenience.la',
needed by 'libstdc++-symbols.explist'.  Stop.
make[6]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src'
Makefile:638: recipe for target 'all-recursive' failed
make[5]: *** [all-recursive] Error 1
make[5]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3/src'
Makefile:507: recipe for target 'all-recursive' failed
make[4]: *** [all-recursive] Error 1
make[4]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3'
Makefile:414: recipe for target 'all' failed
make[3]: *** [all] Error 2
make[3]: Leaving directory
'/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir/x86_64-apple-darwin15.5.0/libstdc++-v3'
Makefile:12290: recipe for target 'all-stage1-target-libstdc++-v3' failed
make[2]: *** [all-stage1-target-libstdc++-v3] Error 2
make[2]: Leaving directory '/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir'
Makefile:21196: recipe for target 'stage1-bubble' failed
make[1]: *** [stage1-bubble] Error 2
make[1]: Leaving directory '/sw/src/fink.build/gcc6-6.0.0-1/darwin_objdir'
Makefile:21500: recipe for target 'bootstrap' failed
make: *** [bootstrap] Error 2