Re: [PATCH] scripts/dtc: consolidate include path options in Makefile

[Frank Rowand <frowand.list@gmail.com>]

On 08/20/18 14:32, Rob Herring wrote:
> On Mon, Aug 20, 2018 at 1:55 PM Frank Rowand <frowand.list@gmail.com> wrote:
>>
>> On 07/03/18 18:59, Masahiro Yamada wrote:
>>> It is tedious to specify extra compiler options for every file.
>>> HOST_EXTRACFLAGS is useful to add options to all files in a
>>> directory.
>>>
>>> -I$(src)/libfdt is needed for all the files in this directory
>>> to include libfdt_env.h etc. from scripts/dtc/libfdt/.
>>>
>>> On the other hand, -I$(src) is used to include check-in headers
>>> from generated C files.  Thus, I added it only to dtc-lexer.lex.o
>>> and dtc-parser.tab.o .
>>>
>>> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>>> ---
>>>
>>>  scripts/dtc/Makefile | 18 ++++--------------
>>>  1 file changed, 4 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
>>> index 9cac65b..1c943e0 100644
>>> --- a/scripts/dtc/Makefile
>>> +++ b/scripts/dtc/Makefile
>>> @@ -9,21 +9,11 @@ dtc-objs    := dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
>>>  dtc-objs     += dtc-lexer.lex.o dtc-parser.tab.o
>>>
>>>  # Source files need to get at the userspace version of libfdt_env.h to compile
>>> +HOST_EXTRACFLAGS := -I$(src)/libfdt
>>
>> Shouldn't that be += instead of :=?
> 
> I don't think so. The definition is local to the file (and reset
> before each makefile is included).
> 
> Rob
> 

Every other place where HOST_EXTRACFLAGS is assigned a value, += is used
instead of :=, including the example in Documentation/kbuild/makefiles.txt

What makes scripts/dtc/Makefile different than the other makefiles?

-Frank