--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -10,6 +10,8 @@
 doCPLC.c     gainquant.c      hpOutput.c  iLBC_define.h   lsf.c          syntFilter.c \
 doCPLC.h     gainquant.h      hpOutput.h  iLBC_encode.c   lsf.h          syntFilter.h 
 
+libilbc_la_LIBADD=-lm
+
 ilbc_includedir=$(includedir)/ilbc
 ilbc_include_HEADERS=iLBC_decode.h iLBC_encode.h iLBC_define.h