On my openSUSE 12.1 I get this:
/usr/lib64/gcc/x86_64-suse-linux/4.6/../../../../x86_64-suse-linux/bin/ld: wmauda.o: undefined reference to symbol 'XSetWMHints'
/usr/lib64/gcc/x86_64-suse-linux/4.6/../../../../x86_64-suse-linux/bin/ld: note: 'XSetWMHints' is defined in DSO /usr/lib64/libX11.so.6 so try adding it to the linker command line
/usr/lib64/libX11.so.6: could not read symbols: Invalid operation
collect2: ld returned 1 exit status
Fix it by adding -lX11 in LIBS.