cmake: Fix typos detected when porting the examples
Hi all,
This MR fixes the following issues detected when porting the Android examples of the monorepo:
- ffmpeg needs
-Wl,-Bsymbolic
for arm64 assembly - monorepo naming convention for
GSTREAMER_ASSETS_DIR
wasn't replicated correctly here - Gradle fallback for
GSTREAMER_ASSETS_DIR
didn't properly escape the CMake current source dir