can't build on CIT with -O0 (warning=error in lalburst cs_gamma.c)

@adam-mercer @duncanmmacleod Trying to compile current master (a143c552) without optimization (-O0) on CIT (ldas-grid). I'm getting the following error; I have no idea what "_FORTIFY_SOURCE" is and why it causes an issue in that specific file. Default gcc there seems to be a very old 4.8.5.

(I've seen @stuart.anderson report issue #206 (closed) with the same file, but it's with a different compiler and doesn't look related at first glance.)

Maybe it's that this tweak e01108ff doesn't work for this old gcc version?

make[7]: Entering directory `/home/david.keitel/git/lalsuite/lalburst/python/lalburst'
  CC       cs_gamma_la-cs_gamma.lo
In file included from /usr/include/limits.h:26:0,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.8.5/include/limits.h:168,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.8.5/include/syslimits.h:7,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.8.5/include/limits.h:34,
                 from /usr/include/python2.7/Python.h:19,
                 from cs_gamma.c:36:
/usr/include/features.h:330:4: error: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror=cpp]
 #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
    ^
cc1: error: unrecognized command line option "-Wno-tautological-compare" [-Werror]
cc1: error: unrecognized command line option "-Wno-misleading-indentation" [-Werror]
cc1: all warnings being treated as errors
make[7]: *** [cs_gamma_la-cs_gamma.lo] Error 1