changes to allow better linking flags in future packages through
pkg-config.
Removed the PKGFS_TEMPLATESDIR, PKGFS_DEPSDIR and others that weren't
too useful. Instead use a single PKGFS_DISTRIBUTIONDIR on which all
those directories/files can be found.
Added a template helper for pkg-config, that changes a pkg-config file
after it's installed to produce correct linker paths.
More helpers could be added in the future.
--HG--
extra : convert_revision : a42fd2e72915a4219714de92579011bca2b0f4a6
