[PATCHES] Makefile.common speedups

Attached are two (orthogonal) patches to make evaluation of Makefile.common a bit faster. The first one is possibly contentious. Currently, early-branching works by checking for the existence of the other branch, by using 'cvs rlog'. That kinda sucks, because it means you can't do 'make local' while disconnected, and even when connected it's not fast. The patch changes it to look for the package's name in a new file, common/early-branched-packages. By keeping that file together with Makefile.common we get pretty much the behaviour we're used to: when build targets change, you have to update common/. Note that if we apply this patch we will also need to create that (empty) file. This would change the cvsadmin procedure for early branching, but hopefully not by a burdensome amount. The second one is just a refactoring to only ask rpm for %VERSION and %RELEASE once. In principle, for packages that overrode both VERSION and RELEASE in their Makefile, this would actually make things slower, since now you'd be forcing rpm to run. According to my pkgcvs checkout, no such packages exist. Tested locally on a 3.2GHz P4. 'time make' baseline was 1.3 seconds. First patch dropped that to about 0.6 seconds. Second patch on top of that dropped down to about 0.38 seconds. - ajax