Bug 1379032 - Use -Oz as optimization flag on android/clang. r=froydnj

Due to android/ndk#133 (comment) and bug 1163171 comment #14, we should use -Oz instead of -Os on Android/clang

MozReview-Commit-ID: 1T6fI87sa33

UltraBlame original commit: 29ef8a111035ecbfd1cc50bd2cab3435384ad0b0

old-configure.in

@@ -7556,12 +7556,6 @@ fi
 MOZ_GFX_OPTIMIZE_MOBILE
 =
 1
-MOZ_OPTIMIZE_FLAGS
-=
-"
--
-Os
-"
 if
 test
 -
@@ -7584,7 +7578,49 @@ fno
 reorder
 -
 functions
+-
+Os
+"
+else
+#
+From
+https
+:
+/
+/
+github
+.
+com
+/
+android
+-
+ndk
+/
+ndk
+/
+issues
+/
+133
+#
+issuecomment
+-
+308549264
+#
+-
+Oz
+is
+smaller
+than
+-
+Os
+on
+clang
+.
 MOZ_OPTIMIZE_FLAGS
+=
+"
+-
+Oz
 "
 fi
 ;