Building from source packages

[Jon Turney]

Recently I've done a little prototyping of a system to build from 
uploaded source packages in a VM, to verify that they recreate packages 
with the same contents as the uploaded packages.

Issues I noted were:

* build time dependencies aren't recorded

Out of the 3135 cygported packages for x86, only 175 set DEPEND.

I don't know how we can ensure DEPEND contains accurate information 
without some sort of build service which tests that it does.

Also, there's probably room here for some policy on what is and isn't 
required in DEPEND i.e. packages essential for building, which are 
already dependencies of cygport, probably don't need to be listed. 
Additionally, some cygclasses probably imply additional build 
dependencies, i.e. 'inherit gnome' implies gnome-common is a build-dep, etc.

Further, turning DEPEND into a list of cygwin packages to install can be 
complex (e.g., if it contains some pkgconfig atoms, it requires 
knowledge of the files contained in all packages to find the one which 
contains a particular .pc file).

* a few packages mistakenly use DEPENDS

A few packages mistakenly use DEPENDS rather than DEPEND, which is 
silently ignored

pkg           maintainer
---           ----------
cloog-isl     Achim Gratz
isl           Achim Gratz
mpclib        Achim Gratz
svn_load_dirs David Rothenberger

* a handful of packages are oddities

These often contain source and patches, but no build script, so the 
configuration used by the maintainer to build the package isn't recorded 
(at least in a way accessible to automation)

pkg       ver         arch
---       ---         ----
bzr       2.6+b2-2    x86    contains source for 2.6b2-1 and 2.6+b2-2
exim      4.86-1      both
fetchmail 6.3.21-1    x86
flex      2.5.39-1    both   orphaned
ipc-utils 1.0-1       x86
mined     2015.25-0   x86_64 a note from maintainer pointing to x86 src
nmh       1.6-2       both   uniquely, g-b-s script name doesn't end .sh
popt      1.16-1      both   orphaned
suite3270 3.3.15ga9-1 both   uniquely, multiple g-b-s and one tarfile