diff --git a/configure.ac b/configure.ac
index 4012a918aae4ef0473e22082fe30fd7478c595db..b90d5d32e8b85554a1fddad9fa36a64d6b63ee77 100644
--- a/configure.ac
+++ b/configure.ac
@@ -185,7 +185,7 @@ fi
 if test "x${PBX_OSTYPE}" = "xLinux" ; then
    AST_EXT_LIB([tonezone], [tone_zone_find], [linux/zaptel.h], [ZAPTEL], [Zaptel])
 else
-   AST_EXT_LIB([tonezone], [tone_zone_find], [zaptel.h], [ZAPTEL], [Zaptel])
+   AST_EXT_LIB([tonezone], [tone_zone_find], [zaptel.h], [ZAPTEL], [Zaptel], [-lm])
 fi
 
 GSM_INTERNAL="yes"