src/Kconfig: Don't treat warns as errors on Clang builds yet

Currently clang/llvm builds are not fully supported. As such,
let us tone down treating errors as warnings until we actually
build the entire tree.

Change-Id: If7f90f9887e27250f5e6d73d1692505676be9d47
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7230
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
diff --git a/src/Kconfig b/src/Kconfig
index 5255130..4deed2a 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -1116,9 +1116,13 @@
 	bool
 	default n
 
+# XXX Currently clang/llvm builds are not fully supported,
+# Let us tone down warns treated as errors until we actually build
+# the whole treee.
 config WARNINGS_ARE_ERRORS
 	bool
-	default y
+	default y if !COMPILER_LLVM_CLANG
+	default n if COMPILER_LLVM_CLANG
 
 # The four POWER_BUTTON_DEFAULT_ENABLE, POWER_BUTTON_DEFAULT_DISABLE,
 # POWER_BUTTON_FORCE_ENABLE and POWER_BUTTON_FORCE_DISABLE options are