make - reassign variable using if-then ?

[Anton Shterenlikht]

On Wed, May 06, 2009 at 11:15:07AM +0200, Mel Flynn wrote:
> On Wednesday 06 May 2009 10:31:53 Anton Shterenlikht wrote:
> > I've this simple makefile:
> >
> > VAR=one
> >
> > all	:	main
> >
> > main	:
> > 	@echo ${.CURDIR}
> > .if ${.CURDIR}
> > 	@echo ${VAR}
> > 	VAR=two
> > 	@echo ${VAR}
> > .endif
> >
> > When I output VAR second time, the value is still "one", and not the
> > new value "two". Why?
> 
> Because it is expanded before being passed to the shell. Sh sees:
> echo one
> VAR=two
> echo one
> 
> What are you really trying to accomplish?

I'm trying to build gcc43 on alpha 6.4.
In /usr/ports/lang/gcc43/Makefile I have:

# grep NOT_FOR_ARCHS /usr/ports/lang/gcc43/Makefile 
NOT_FOR_ARCHS=  alpha ia64 powerpc
# 

In /etc/make.conf I have:

.if ${.CURDIR:M*/lang/gcc43*}
NOT_FOR_ARCHS= ia64
USE_GCC=4.3+
.endif

This used to work fine until some update. Not anymore.
The second setting is being used, i.e. the port is being built
with gcc43. But the NOT_FOR_ARCHS is not changed, so I have
to do it manually each time. 

So I tried to experiment with changing variable values withing if-then.

many thanks
anton

-- 
Anton Shterenlikht
Room 2.6, Queen's Building
Mech Eng Dept
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