I had a problem with "./build static" iaxmodem-1.3.0 on Ubuntu 14.04. Seems a gcc bug. Here is my solution: Just edit "build" file, line 48: gcc -lm $LLIBS -ltiff -o iaxmodem iaxmodem.o lib/spandsp/src/.libs/libspandsp.a lib/libiax2/src/.libs/libiax.a And move the -lm to THE END: gcc $LLIBS -ltiff -o iaxmodem iaxmodem.o lib/spandsp/src/.libs/libspandsp.a lib/libiax2/src/.libs/libiax.a -lm Now it works :-) Making all in src make[1]: Entering directory `/tmp/iaxmodem-1.3.0/lib/spandsp/src' make all-am...