Bug#944337: debhelper: makefile buildsystem: pass cross tools for all targets

[Helmut Grohne <helmut@subdivi.de>]

Package: debhelper
Version: 12.7.1
Severity: wishlist
User: debian-cross@lists.debian.org
Usertags: ftcbfs
Control: affects -1 + src:baresip

Hi Niels and d-cross@l.d.o,

I'm observing a pattern and would like to seek consensus about a change
in debhelper's makefile buildsystem. A number of makefiles (not hugely
many, but every now and then) detect features from CC or PKG_CONFIG and
behave differently not only during the default target but also during
the install or clean target. However, only dh_auto_build passes cross
tools along. In these cases, one has to explicitly pass CC and/or
PKG_CONFIG along or export them as environment variables. Can we fix
that more centrally? In debhelper?

There are a few caveats here that I'd like to consider before going that
route.

Some build systems use non-filenames as targets. The absence of the
files causes a rebuild during make install. The current debhelper
practise has made these cases visible and in such cases, I've usually
sent patches fixing up the dependencies. The proposed change would make
them invisible again.

Another aspect is that some packages use multiple (debhelper)
buildsystems and vary them on a per-target basis. Changing the behaviour
here bears a small risk for (cross build) regressions. This particular
problem seems more relevant to the clean target than the install target
though, so we could change only make install as a compromise.

What do you think about the general idea and the impact? baresip is a
recent example where this is applicable for make install.

Helmut