Fix gfxstream Magma build

- use pkg-config to look for libmagma.a: this is more standard
  in "Linux-distro" style builds rather Meson wrap files.

- don't use magma_fuchsia_log(..) with the gfxstream build.  The
  specialized logger should likely be only needed for Fuchsia
  builds, since mesa_loge(..) already has hooks for Android/Linux.

BUG=326101772
TEST=compile with related gfxstream patches

Change-Id: I4f962b54da8580b298a0126e67ba16563f1acc10
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/mesa/+/994038
Reviewed-by: Craig Stout <cstout@google.com>
Commit-Queue: Gurchetan Singh <gurchetansingh@google.com>
2 files changed