[Bug bootstrap/81037] New: Xcode 9 requires back ports on gcc-5-branch and gcc-6-branch for bootstrapping under Xcode 9

[howarth.at.gcc at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81037

            Bug ID: 81037
           Summary: Xcode 9 requires back ports on gcc-5-branch and
                    gcc-6-branch for bootstrapping under Xcode 9
           Product: gcc
           Version: unknown
            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: ---

Current gcc-5-branch and gcc-6-branch fails to bootstrap against Xcode 9 beta
on 10.12 due to the absence of back ports from gcc-7-branch (which does
bootstrap). The first issue is the bootstrap failure of...

g++ -std=gnu++98 -fno-PIE -c -g -DIN_GCC -fno-strict-aliasing -fno-exceptions
-fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wno-format -Wmissing-format-attribute -Woverloaded-virtual
-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings
-fno-common -DHAVE_CONFIG_H -o darwin-driver.o darwin-driver.ii

../../gcc-6.3.0/gcc/config/darwin-driver.c:302:13: error: cannot initialize a
variable of type 'char *' with an rvalue of type
      'const char *'
      char *first_period = strchr(vers_string, '.');
            ^              ~~~~~~~~~~~~~~~~~~~~~~~~
Back porting the fix from 

https://github.com/gcc-mirror/gcc/commit/5972cd58bde3bc8bacfe994e5b127c411241f255.patch

The second failure specific to gcc-5-branch is...

g++ -c -g -DIN_GCC -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W
-Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format
-Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long
-Wno-variadic-macros -Wno-overlength-strings -fno-common -DHAVE_CONFIG_H -o
auto-profile.o auto-profile.ii

In file included from ../../gcc-5.4.0/gcc/auto-profile.c:26:
In file included from
/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/map:446:
/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/functional:1398:2:
error: no member
      named 'fancy_abort' in namespace 'std::__1'; did you mean simply
'fancy_abort'?
 std::__1::fancy_abort
("/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/func...
 ^~~~~~~~~~

I suspect this can be fixed by back porting both...

https://github.com/gcc-mirror/gcc/commit/49622efa89937fa310add53b1efb50273ec0d857

and

https://github.com/gcc-mirror/gcc/commit/ec8c949f8f296d1270fc41404175cd7249df4cd4

Unfortunately the second patch doesn't apply cleaning on gcc-5-branch and may
require additional back ports to do so.