Split [CC|CXX]_WRAPPER from [TARGET|HOST]_[CC|CXX]

- Don't overwrite [TARGET|HOST]_[CC|CXX] with the [CC|CXX]_WRAPPER prefix,
  so that we can disable the wrapper per module.
- Disable ccache on a module when FDO is enabled.

Bug: 22612634
Change-Id: Ibc04a4742d589955066c7eceb43a0da9a2b893bc
(cherry-pick from commit c671a7cf5cae42b61991d9b72e53d9d8a6ace84e)
diff --git a/core/config.mk b/core/config.mk
index 88a1bcb..9c78477 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -257,6 +257,8 @@
 include $(BUILD_SYSTEM)/combo/select.mk
 endif
 
+include $(BUILD_SYSTEM)/ccache.mk
+
 ifdef TARGET_PREFER_32_BIT
 TARGET_PREFER_32_BIT_APPS := true
 TARGET_PREFER_32_BIT_EXECUTABLES := true