'pkg-config --libs' shouldn't return -lm

[yurivict]

$ pkg-config --cflags --libs ccd
-I/usr/local/include -L/usr/local/lib -lccd -lm 

libccd.so is already linked to libm.so:

$ ldd -a /usr/local/lib/libccd.so
/usr/local/lib/libccd.so:
	libm.so.5 => /lib/libm.so.5 (0x801208000)
	libc.so.7 => /lib/libc.so.7 (0x800823000)
/lib/libm.so.5:
	libc.so.7 => /lib/libc.so.7 (0x800823000)

There is no need to make the user program to also link with libm.so.