test/avcenc: link with -lpthread.
test/avcenc: link with -lpthread.

Otherwise it will complain during compiling:
usr/bin/ld: avcenc.o: undefined reference to symbol 'pthread_create@@GLIBC_2.2.5'
/usr/bin/ld: note: 'pthread_create@@GLIBC_2.2.5' is defined in DSO

Signed-off-by: Zhao Yakui <21bae65ecea50a19bd9d0fef489914760189fd5b@intel.com>

android-ia/hardware_intel_libva,android-ia/hardware_intel_libva,CyanogenMod/android_hardware_intel_libva,CyanogenMod/android_hardware_intel_libva,halleyzhao/libva-fdo,halleyzhao/libva-fdo,android-ia/hardware_intel_libva,CyanogenMod/android_hardware_intel_libva,halleyzhao/libva-fdo