Mine

gmake[1]: Entering directory `/usr/home/vision/work/gpac/applications'
set -e; for i in mp4box mp4client generators osmozilla ; do gmake -C $i all; done 
gmake[2]: Entering directory `/usr/home/vision/work/gpac/applications/mp4box'
gcc -Wl,--warn-common -export-dynamic -o ../../bin/gcc/MP4Box main.o filedump.o fileimport.o -L../../bin/gcc -lgpac -lz -pthread
gmake[2]: Leaving directory `/usr/home/vision/work/gpac/applications/mp4box'
gmake[2]: Entering directory `/usr/home/vision/work/gpac/applications/mp4client'
gcc -O3  -pthread -fno-strict-aliasing -Wall -I/usr/home/vision/work/gpac/include  -c -o main.o main.c 
main.c: In function `main':
main.c:1062: warning: too many arguments for format
gcc -O3  -pthread -fno-strict-aliasing -Wall -I/usr/home/vision/work/gpac/include  -c -o extract.o extract.c 
gcc -Wl,--warn-common -export-dynamic -o ../../bin/gcc/MP4Client main.o extract.o -L../../bin/gcc -lgpac -lz
../../bin/gcc/libgpac.so: undefined reference to `pthread_create'
../../bin/gcc/libgpac.so: undefined reference to `pthread_attr_init'
../../bin/gcc/libgpac.so: undefined reference to `pthread_exit'
../../bin/gcc/libgpac.so: undefined reference to `pthread_cancel'
../../bin/gcc/libgpac.so: undefined reference to `pthread_setschedparam'
../../bin/gcc/libgpac.so: undefined reference to `pthread_attr_setdetachstate'
../../bin/gcc/libgpac.so: undefined reference to `pthread_join'
gmake[2]: *** [MP4Client] Error 1
gmake[2]: Leaving directory `/usr/home/vision/work/gpac/applications/mp4client'
gmake[1]: *** [apps] Error 2
gmake[1]: Leaving directory `/usr/home/vision/work/gpac/applications'
gmake: *** [apps] Error 2