Bug 1480006 - Enable LTO on Android CI builds. r=froydnj

mobile/android/config/mozconfigs/android-aarch64/nightly

@@ -6,6 +6,12 @@ ac_add_options --target=aarch64-linux-android
 
 ac_add_options --with-branding=mobile/android/branding/nightly
 
+export AR="$topsrcdir/clang/bin/llvm-ar"
+export NM="$topsrcdir/clang/bin/llvm-nm"
+export RANLIB="$topsrcdir/clang/bin/llvm-ranlib"
+
+ac_add_options --enable-lto
+
 export MOZILLA_OFFICIAL=1
 export MOZ_TELEMETRY_REPORTING=1
 export MOZ_ANDROID_POCKET=1

mobile/android/config/mozconfigs/android-api-16/nightly

@@ -16,4 +16,10 @@ export MOZ_TELEMETRY_REPORTING=1
 export MOZ_ANDROID_MMA=1
 export MOZ_ANDROID_POCKET=1
 
+export AR="$topsrcdir/clang/bin/llvm-ar"
+export NM="$topsrcdir/clang/bin/llvm-nm"
+export RANLIB="$topsrcdir/clang/bin/llvm-ranlib"
+
+ac_add_options --enable-lto
+
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"

mobile/android/config/mozconfigs/android-x86/nightly

@@ -14,4 +14,10 @@ export MOZILLA_OFFICIAL=1
 export MOZ_TELEMETRY_REPORTING=1
 export MOZ_ANDROID_POCKET=1
 
+export AR="$topsrcdir/clang/bin/llvm-ar"
+export NM="$topsrcdir/clang/bin/llvm-nm"
+export RANLIB="$topsrcdir/clang/bin/llvm-ranlib"
+
+ac_add_options --enable-lto
+
 . "$topsrcdir/mobile/android/config/mozconfigs/common.override"