[Bug go/81451] New: missing futex check - libgo/runtime/thread-linux.c:12:0 futex.h:13:12: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘long’

[mfe at live dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81451

            Bug ID: 81451
           Summary: missing futex check -
                    libgo/runtime/thread-linux.c:12:0 futex.h:13:12:
                    error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or
                    ‘__attribute__’ before ‘long’
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: mfe at live dot de
                CC: cmang at google dot com
  Target Milestone: ---

Created attachment 41765
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41765&action=edit
futex of host system

the exact version of GCC:
gcc-7.1.0

the system type:
NetgearReadyNAS Duo
(http://wiki.dietpc.org/index.php/DIET-PC_on_SPARC_ReadyNAS)

the options given when GCC was configured/built:
configure CC=/opt/gcc-4.6/bin/gcc CXX=/opt/gcc-4.6/bin/g++
--enable-languages=c,c++,go --prefix=/opt/gcc-7.1  --with-cpu=v7
--with-mpc=/usr/local  --with-mpfr=/usr/local --with-gmp=/usr/local
--with-isl=/usr/local/ --disable-libstdcxx-pch 

the complete command line that triggers the bug;
/usr/local/bin/make

the compiler output (error messages, warnings, etc.);
[...]
/bin/sh ./libtool  --tag=CC   --mode=compile /media/gcc-7.1-compiled/./gcc/xgcc
-B/media/gcc-7.1-compiled/./gcc/ -B/opt/gcc-7.1/sparc-unknown-linux-gnu/bin/
-B/opt/gcc-7.1/sparc-unknown-linux-gnu/lib/ -isystem
/opt/gcc-7.1/sparc-unknown-linux-gnu/include -isystem
/opt/gcc-7.1/sparc-unknown-linux-gnu/sys-include    -DHAVE_CONFIG_H -I.
-I../../../gcc-7.1.0/libgo  -I ../../../gcc-7.1.0/libgo/runtime
-I../../../gcc-7.1.0/libgo/../libffi/include -I../libffi/include -pthread 
-fexceptions -fnon-call-exceptions -fplan9-extensions  -Wall -Wextra
-Wwrite-strings -Wcast-qual -Werror   -D_GNU_SOURCE -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -I ../../../gcc-7.1.0/libgo/../libgcc -I
../../../gcc-7.1.0/libgo/../libbacktrace -I ../../gcc/include -g -O2 -MT
thread-linux.lo -MD -MP -MF .deps/thread-linux.Tpo -c -o thread-linux.lo `test
-f 'runtime/thread-linux.c' || echo
'../../../gcc-7.1.0/libgo/'`runtime/thread-linux.c
libtool: compile:  /media/gcc-7.1-compiled/./gcc/xgcc
-B/media/gcc-7.1-compiled/./gcc/ -B/opt/gcc-7.1/sparc-unknown-linux-gnu/bin/
-B/opt/gcc-7.1/sparc-unknown-linux-gnu/lib/ -isystem
/opt/gcc-7.1/sparc-unknown-linux-gnu/include -isystem
/opt/gcc-7.1/sparc-unknown-linux-gnu/sys-include -DHAVE_CONFIG_H -I.
-I../../../gcc-7.1.0/libgo -I ../../../gcc-7.1.0/libgo/runtime
-I../../../gcc-7.1.0/libgo/../libffi/include -I../libffi/include -pthread
-fexceptions -fnon-call-exceptions -fplan9-extensions -Wall -Wextra
-Wwrite-strings -Wcast-qual -Werror -D_GNU_SOURCE -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -I ../../../gcc-7.1.0/libgo/../libgcc -I
../../../gcc-7.1.0/libgo/../libbacktrace -I ../../gcc/include -g -O2 -MT
thread-linux.lo -MD -MP -MF .deps/thread-linux.Tpo -c
../../../gcc-7.1.0/libgo/runtime/thread-linux.c  -fPIC -DPIC -o
.libs/thread-linux.o
In file included from ../../../gcc-7.1.0/libgo/runtime/thread-linux.c:12:0:
/usr/include/linux/futex.h:13:12: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or
‘__attribute__’ before ‘long’
 asmlinkage long sys_futex(u32 __user *uaddr, int op, int val,
            ^~~~
make[4]: *** [Makefile:1944: thread-linux.lo] Error 1

I'm not sure, but it looks like gcc is expecting a newer version of futex.h
than the host system can provide?

I attached the futex header of the host system which is running the Linux
kernel 2.6.17.14.

Maybe --disable-linux-futex would fix the issue? Is it possible to add manual
the configure parameter --disable-linux-futex afterwards to the libgo
dictionary without reconfiguring and recompiling the current gcc?