building '_helpers' extension
creating build
creating build/temp.linux-x86_64-2.7
gcc -pthread -DNDEBUG -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector --param=ssp-buffer-size=4 -Wall -O2 -Werror -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector --param=ssp-buffer-size=4 -D_FORTIFY_SOURCE=2 -fPIC -I/usr/include/python2.7 -c _helpers.c -o build/temp.linux-x86_64-2.7/_helpers.o
In file included from /usr/include/python2.7/Python.h:8:0,
                 from _helpers.c:32:
/usr/include/python2.7/pyconfig.h:1173:0: error: "_POSIX_C_SOURCE" redefined [-Werror]
 #define _POSIX_C_SOURCE 200112L
 ^
In file included from /usr/include/assert.h:35:0,
                 from _helpers.c:5:
/usr/include/features.h:228:0: note: this is the location of the previous definition
 #  define _POSIX_C_SOURCE 200809L
 ^
cc1: all warnings being treated as errors
error: command 'gcc' failed with exit status 1
make: *** [lib/bup/_helpers.so] Error 1