[TRIVIAL PATCH] of: per-file dtc preprocessor flags

[Eugeniy Paltsev]

As of today we are able to pass custom flags to dtc compiler but not
to dtc preprocessor.
This ability is required for including some board-specific header files.
It allows us to pass defined constants to dts without their duplication
in several places.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
 scripts/Makefile.lib | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index f1f38c8cdc74..f2595a608dce 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -166,6 +166,8 @@ dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
 		 $(addprefix -I,$(DTC_INCLUDE))                          \
 		 -undef -D__DTS__
 
+dtc_cpp_flags  += $(DTC_CPP_FLAGS_$(basetarget))
+
 # Useful for describing the dependency of composite objects
 # Usage:
 #   $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
-- 
2.21.0