graphite: Force optimization on Android.

The Pass.cpp triggers an infinite loop in clang when not optimizing (ie.
with the debugging buildls), at least with this version:

  > ~/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ --version
  Android (5058415 based on r339409) clang version 8.0.2 (https://android.googlesource.com/toolchain/clang 40173bab62ec746213857d083c0e8b0abb568790) (https://android.googlesource.com/toolchain/llvm 7a6618d69e7e8111e1d49dc9e7813767c5ca756a) (based on LLVM 8.0.2svn)
  Target: x86_64-unknown-linux-gnu
  Thread model: posix
  InstalledDir: /local/home/kendy/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/linux-x86_64/bin

Change-Id: Ib4984f8838fc733be6da4e24eb10915d3efbf79e

external/graphite/StaticLibrary_graphite.mk

@@ -32,6 +32,15 @@ $(eval $(call gb_StaticLibrary_add_cxxflags,graphite,\
 endif
 endif
 
+ifeq ($(OS),ANDROID)
+# Force optimizations on Android, because otherwise Pass.cpp triggers an
+# infinite loop in clang, at least in this version:
+# Android (5058415 based on r339409) clang version 8.0.2 (https://android.googlesource.com/toolchain/clang 40173bab62ec746213857d083c0e8b0abb568790) (https://android.googlesource.com/toolchain/llvm 7a6618d69e7e8111e1d49dc9e7813767c5ca756a) (based on LLVM 8.0.2svn)
+$(eval $(call gb_StaticLibrary_add_cxxflags,graphite,\
+     -Os \
+))
+endif
+
 $(eval $(call gb_StaticLibrary_set_generated_cxx_suffix,graphite,cpp))
 
 $(eval $(call gb_StaticLibrary_add_generated_exception_objects,graphite,\