liba52: Disable `-prefer-non-pic` to enable `-fPIC`.

liba52: Disable `-prefer-non-pic` to enable `-fPIC`.

Using GCC 4.4.2 and Binutils 2.20 gives the following error.

    …/bin/ld: .libs/imdct.o: relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC

Therefore enable `-fPIC` with this patch taken from Debian [1].

[1] http://patch-tracker.debian.org/patch/series/view/a52dec/0.7.4-13/01-enable-pic.diff

Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Philip Balister <philip@balister.org>