Re: [Gnu-arch-users] Re: Build System links/ recommendations

[Robin Farine]

On Sunday 05 September 2004 09.23, Jan Hudec wrote:
> On Sun, Sep 05, 2004 at 02:12:38 +0200, Robin Farine wrote:

> > This looks too simple so I must have missed something, but it
> > looks like it is equivalent.

> So try it ;-). You'll find out it isn't. It checks the timestamp
> on subdir/mylib too early and even if the subdir makefile does
> something, myprog is not relinked.

:) OK, it _was_ too simple.

The introduction of an intermediate target that is not updated 
unless it does not exist seems to solve (?) the problem.

* Makefile:

myprog: subdir-libs.dummy subdir/mylib
        touch $@

subdir-libs.dummy: subdir-libs
        @test -f $@ || touch $@

.PHONY: subdir-libs
subdir-libs:
        $(MAKE) -C subdir libs


* subdir/Makefile:

.PHONY: libs
libs: mylib

mylib: ronron
        touch $@

ronron:
        touch $@