Tip to speed-up pkgsrc compilation on small devices

[tlaronde%polynum.com@localhost]

This could be useful to others since I haven't find it before diving in
pkgsrc/mk.

Context: in order to compile natively on a "small" ARM machine packages
that don't cross-compile, I wanted to speed up the process by putting
WRKOBJDIR on a tmpfs.

Obviously, I don't want to clutter the memory with useless files: once
installed, the package work dir shall be cleaned. This means that for
all dependencies make a "make install clean"

Solution: I wandered in pkgsrc/mk to see what to modify or what variable
I could set to obtain this. DEPENDS_TARGET was, almost, what I needed
when I stumbled upon the target "bin-install"
(mk/install/bin-install.mk)

So typing :

$ make bin-install

does recursively fetch the binary package if available, compile it from
source if not and clean the dir when the dependency is installed.

One can suppress implicit searching on the Web by setting BINPKG_SITES

One unfelicity: if run not as privileged user, it first su to try to
pkg_add before perhaps finding there is not such package, before
dropping root and returning to build.
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
                     http://www.kergis.com/
                       http://www.sbfa.fr/
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