[Bug libstdc++/77814] New: build fails trying to build eh_arm

["tprince at computer dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77814

            Bug ID: 77814
           Summary: build fails trying to build eh_arm
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tprince at computer dot org
  Target Milestone: ---

Created attachment 39729
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39729&action=edit
log from trunk stage 1 bootstrap of libstdc++

Initial bootstrap tries (and fails) to build eh_arm.

/cygdrive/c/users/tim/tim/tim/src/gnu/gcc2/libstdc++-v3/include/bits/std_abs.h:
In function ‘long long int std::abs(long long int)’:
/cygdrive/c/users/tim/tim/tim/src/gnu/gcc2/libstdc++-v3/include/bits/std_abs.h:5
9:3: error: conflicting declaration of C function ‘long long int std::abs(long
l
ong int)’
   abs(long long __x) { return __builtin_llabs (__x); }
   ^~~

full log attached

Guessing that the build shouldn't require this compilation.