[gpsd-dev] Fedora 24, gcc 6.1.1 - 'memory_order_seq_cst' was not declared in this scope

[Jason Azze]

Summary: Build of release-3.16-486-ga3ff750 broken on Fedora 24 (Linux
4.7.3) using gcc 6.1.1, glibc 2.23

Probably identical to this Debian bug:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=830993

Apologies if this is a repeat report. I know we've seen problems on
Fedora with our old friend, atomic_thread_fence, before. I was trying
to see if I could reproduce (with Fedora) some build errors with the
Debian gcc 6 build that bzed re-reported on irc last night. I got
these errors instead. This means gpsd won't build on the latest Fedora
or Debian releases using their default gcc.

In file included from clock_gettime.c:10:0:
compiler.h: In function 'void memory_barrier()':
compiler.h:93:25: error: 'memory_order_seq_cst' was not declared in this scope
     atomic_thread_fence(memory_order_seq_cst);
                         ^~~~~~~~~~~~~~~~~~~~
compiler.h:93:25: note: suggested alternative:
In file included from /usr/include/c++/6.1.1/atomic:41:0,
                 from compiler.h:75,
                 from clock_gettime.c:10:
/usr/include/c++/6.1.1/bits/atomic_base.h:62:7: note:   'memory_order_seq_cst'
       memory_order_seq_cst
       ^~~~~~~~~~~~~~~~~~~~
In file included from clock_gettime.c:10:0:
compiler.h:93:45: error: 'atomic_thread_fence' was not declared in this scope
     atomic_thread_fence(memory_order_seq_cst);
                                             ^
compiler.h:93:45: note: suggested alternative:
In file included from /usr/include/c++/6.1.1/atomic:41:0,
                 from compiler.h:75,
                 from clock_gettime.c:10:
/usr/include/c++/6.1.1/bits/atomic_base.h:101:3: note:
'std::atomic_thread_fence'
   atomic_thread_fence(memory_order __m) noexcept
   ^~~~~~~~~~~~~~~~~~~
scons: *** [qt-clock_gettime.os] Error 1
scons: building terminated because of errors.

I have attached a gzipped (to protect from munging in transit) report
with more detail.
Or see it here: http://hastebin.com/raw/izeruqefuv

gpsd-fedora24-gcc6.txt.gz
Description: GNU Zip compressed data