Make Clang host builds hermetic on Linux.

This lays the groundwork for making builds hermetic on Darwin as well.
That will be fixed in a future patch.

bug 13435344

Change-Id: Iae82d0b9efad0598d682ff5fd4daa737aa607866
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index 037dee6..994196a 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -156,3 +156,7 @@
 define get-file-size
 stat -f "%z" $(1)
 endef
+
+# gcc location for clang; to be updated when clang is updated
+# HOST_TOOLCHAIN_ROOT is a Darwin-specific define
+HOST_TOOLCHAIN_FOR_CLANG := $(HOST_TOOLCHAIN_ROOT)
\ No newline at end of file