Re: [PATCH trace-cmd 3/3] Revert "trace-cmd: Use conditionalassignment of CC and AR"

From: David Sharp
Date: Thu Mar 10 2011 - 00:25:44 EST


On Wed, Mar 9, 2011 at 7:26 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Wed, 2011-03-09 at 21:51 -0500, Steven Rostedt wrote:
>
>> I'll play with some other make tricks and see if I can come up with a
>> better solution.
>
> OK, it didn't take me long to come up with "Makefiles suck" ;)

Yes, except for very basic things.

>
> But I did come up with a solution:
>
> ifneq ("$(origin CC)", "environment")
> CC = gcc
> endif
>
> CC := $(CROSS_COMPILE)$(CC)
>
> This wont let make CC=xx work unless I also add a:
>
> ifneq ("$(origin CC)", "command line")
>
> around the above if, but do we care?
>
> -- Steve

This seems to do it all:

define allow-override
$(if $(or $(findstring environment,$(origin $(1))),
$(findstring command line,$(origin $(1)))),,\
$(eval $(1) = $(2)))
endef

$(call allow-override,CC,$(CROSS_COMPILE)gcc)
$(call allow-override,AR,$(CROSS_COMPILE)ar)
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