[RFC PATCH 1/3] kbuild: introduce cmd_dtc_cpp

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

cmd_dtc_cpp runs the C pre-processor on the input .dts file before
passing it to dtc for final compilation. This allows used of #define
within the .dts file.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 scripts/Makefile.lib |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 0be6f11..e3a149e 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -266,6 +266,9 @@ $(obj)/%.dtb.S: $(obj)/%.dtb
 quiet_cmd_dtc = DTC     $@
 cmd_dtc = $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) -d $(depfile) $<
 
+quiet_cmd_dtc_cpp = DTC+CPP $@
+cmd_dtc_cpp = $(CC) -E -Wp,-MD,$(depfile) -xc $< | $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) -
+
 # Bzip2
 # ---------------------------------------------------------------------------
 
-- 
1.7.0.4