gstreamer-full: Fix link with x264
If a static build is requested and x264 plugin has been enabled the full link fails with:
/usr/bin/ld: subprojects/x264/libx264.a(cabac-a.o): relocation R_X86_64_PC32 against symbol `x264_cabac_range_lps' can not be used when making a shared object; recompile with -fPIC
Fixes #108 (closed)