[PATCH] Makefile: Allow to override CPP variable

[Paul Menzel]

      Date: Sat, 23 May 2015 16:02:08 +0200

Using the conditional assignment operator `?=` [1] instead of `=` makes
it possible to override the variable `CPP` by using an environment
variable

	$ CPP=cpp-5 make

or directly setting it.

	$ make CPP=cpp-5

[1] https://www.gnu.org/software/make/manual/make.html#Setting

Signed-off-by: Paul Menzel <paulepanter(a)users.sourceforge.net>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 01cadda..63bff49 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ OBJCOPY=$(CROSS_PREFIX)objcopy
 OBJDUMP=$(CROSS_PREFIX)objdump
 STRIP=$(CROSS_PREFIX)strip
 PYTHON=python
-CPP=cpp
+CPP?=cpp
 IASL:=iasl
 LD32BIT_FLAG:=-melf_i386
 
-- 
2.1.4

[Kevin O'Connor]

      On Sat, May 23, 2015 at 04:15:47PM +0200, Paul Menzel wrote:
  Date: Sat, 23 May 2015 16:02:08 +0200
 
 Using the conditional assignment operator `?=` [1] instead of `=` makes
 it possible to override the variable `CPP` by using an environment
 variable
 
 	$ CPP=cpp-5 make
 
 or directly setting it.
 
 	$ make CPP=cpp-5
I think picking up build definitions from the environment is
confusing.  The second form you show above should work today, and I
think it is sufficient for those needing to override build
definitions.

-Kevin