Revert "Handle Clang's change of defaults from -fcommon to -fno-common"

This reverts commit a4a4d29509289d4808f986cff26b4171ffc97fc0.

Reason for revert: DroidMonitor-triggered revert due to breakage https://android-build.googleplex.com/builds/quarterdeck?branch=git_udc-dev-plus-aosp&target=aosp_cheetah-trunk_staging-userdebug&lkgb=10647066&lkbb=10647484&fkbb=10647184, bug 295551355.

Bug: 295551355

Change-Id: I9b68cdac258b26f975e1e575a383b789c87adaa4
diff --git a/cc/config/global.go b/cc/config/global.go
index e547c3f..ff5ab05 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -68,6 +68,10 @@
 		// not emit the table by default on Android since NDK still uses GNU binutils.
 		"-faddrsig",
 
+		// Turn on -fcommon explicitly, since Clang now defaults to -fno-common. The cleanup bug
+		// tracking this is http://b/151457797.
+		"-fcommon",
+
 		// Help catch common 32/64-bit errors.
 		"-Werror=int-conversion",