mysql_config produces invalid cflags (was: udf_example.c couldn't compile)

[mikhail@localhost udf]$ ls -la

total 36

drwxrwxr-x. 1 mikhail mikhail    26 ноя  5 23:02 .

drwxrwxr-x. 1 mikhail mikhail  5816 ноя  5 22:42 ..

-rw-r--r--. 1 mikhail mikhail 33593 сен 25 04:29 udf_example.c

[mikhail@localhost udf]$ mysql_config --cflags

-I/usr/include/mysql -g -pipe -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fPIC -fno-delete-null-pointer-checks  -g -static-libgcc -fno-omit-frame-pointer -fno-strict-aliasing

[mikhail@localhost udf]$ gcc $(mysql_config --cflags) -shared -fPIC -o udf_example.so udf_example.c

cc1: error: -Wformat-security ignored without -Wformat [-Werror=format-security]

In file included from /usr/include/pthread.h:21:0,

                 from /usr/include/mysql/my_global.h:294,

                 from udf_example.c:128:

/usr/include/features.h:328:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]

 #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)

    ^

cc1: some warnings being treated as errors