I had the following error while compiling yelp today

In file included from yelp-debug.c:26:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^
cc1: all warnings being treated as errors
Makefile:597: recipe for target 'libyelp_la-yelp-debug.lo' failed
make[3]: *** [libyelp_la-yelp-debug.lo] Error 1
make[3]: *** Attente des tâches non terminées....
In file included from yelp-document.c:29:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^
In file included from yelp-docbook-document.c:37:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^
In file included from yelp-info-document.c:35:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^
In file included from yelp-info-parser.c:31:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^
cc1: all warnings being treated as errors
Makefile:632: recipe for target 'libyelp_la-yelp-info-document.lo' failed
make[3]: *** [libyelp_la-yelp-info-document.lo] Error 1
In file included from yelp-mallard-document.c:38:0:
yelp-debug.h:38:5: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 #if __STDC_VERSION__ < 199901L
     ^
yelp-debug.h:55:6: error: "__STDC_VERSION__" is not defined [-Werror=undef]
 # if __STDC_VERSION__ < 199901L
      ^

I'm using fedora 21
$ rpm -qa gcc
gcc-4.9.2-1.fc21.x86_64
$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.9.2/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.9.2-20141101/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.9.2-20141101/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix