Here is the complier error (sorry for pasting it in here, but you'll see why it's important in a second...) Creating mod_amr.so... /usr/lib/gcc/i686-redhat-linux/4.4.3/../../../crt1.o: In function `_start': (.text+0x18): undefined reference to `main' collect2: ld returned 1 exit status quiet_libtool: link: gcc -I/home/dhubler/work/freeswitch/src/include -I/home/dhubler/work/freeswitch/src/include -I/home/dhubler/work/freeswitch/libs/libteletone/src -fPIC -Werror -fvisibility=hidden -DSWITCH_API_VISIBILITY=1 -DHAVE_VISIBILITY=1 -g -ggdb -g -O2 -Wall -std=c99 -pedantic -Wdeclaration-after-statement -D_GNU_SOURCE -DAMR_PASSTHROUGH -o .libs/mod_amr.so -Wl,-x .libs/mod_amr.o -lm /home/dhubler/work/freeswitch/.libs/libfreeswitch.so -L/home/dhubler/work/freeswitch/libs/apr-util/xml/expat/lib /home/dhubler/work/freeswitch/libs/apr-util/xml/expat/lib/.libs/libexpat.a /home/dhubler/work/freeswitch/libs/apr/.libs/libapr-1.a -lpq -luuid -lrt -lcrypt -lpthread -lssl -lcrypto -ldl -lz -lncurses -Wl,-rpath -Wl,/usr/local/freeswitch/lib -Wl,-rpath -Wl,/usr/local/freeswitch/mod For some reason "-shared" is not on the link line Don't ask me how i figured this out, but If I change in file build/modmake.rules SOLINK = -shared -Xlinker -x to SOLINK = --shared -Xlinker -x Everything compiles and freeswitch runs. Something in the gnu tool chain wants to strip out any "-foo" parameter to gcc but adding an extra "-" it allows it through. So i didn't find the problem, but i did find a weird workaround.