stlport: Force building PIC code

Required for gcc 4.7

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
stlport: Fix strict aliasing violations

This patch fixes strict aliasing violations.
Forward-ported from Chao Yang <chao.yang@linaro.org>'s
patch for 2.3.5.

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
Fix compilation with clang and GCC 4.7

See 34ed92a1b33fc95e1bf48a7f1840ddbcbacb5e3e and
7414fafb3c392b0fee2932afd175a4ed0950aae9

Change-Id: I7c4e1ffda33ff9be134df1f2e4c8b4e627526936