log() function not available in libgmp, need libm too

--- setup.py
+++ setup.py
@@ -349,7 +349,7 @@ kw = {'name':"pycrypto",
             # _fastmath (uses GNU mp library)
             Extension("Crypto.PublicKey._fastmath",
                       include_dirs=['src/','/usr/include/'],
-                      libraries=['gmp'],
+                      libraries=['gmp','m'],
                       sources=["src/_fastmath.c"]),
 
             # Hash functions