Overhaul "haiku" PackageInfo.

* Merge all except the x86_gcc2 one into a single "generic" one.
   It is now exactly the same on all architectures, save a single
   ifdef for x86_64, which needs a different compat version, as there
   are still some packages built that far back and never rebuilt since!

 * Group the requires according to category: first any arch packages,
   then commands, then the GCC syslibs, then packages always depended
   upon if they are available, and finally packages only depended upon
   in "regular" builds.

 * Put all packages inside HAIKU_BUILD_FEATURE_* ifdef tests,
   and order them alphabetically within their category.

If I have done this all correctly, at least x86_64 should get an
identically generated haiku .PackageInfo as before this commit, save
the reordering changes. Others may differ based on package availability,
as they were missing the requisite #ifdef sections.

build/jam/PackageRules

@@ -114,7 +114,7 @@ rule PreprocessPackageOrRepositoryInfo target : source : architecture
 	}
 	for feature in $(HAIKU_BUILD_FEATURES) {
 		local featureSplit = [ FSplitString $(feature) : ":" ] ;
-		defines += HAIKU_BUILD_FEATURE_$(featureSplit:UJ=_)_ENABLED ;
+		defines += HAIKU_BUILD_FEATURE_$(featureSplit:J=_)_ENABLED ;
 	}
 
 	local revisionFile = [ DetermineHaikuRevision ] ;