Install pkg-config files.

* Makefile.in: Define $(pkgconfig_dir).

* build/generator/gen_make.py
  (Generator.write.file_to_eztdata): Add fields for pkg-config data.
  (Generator.write): Generate install rules for pkg-config files.

* build/generator/templates/build-outputs.mk.ezt:
  Add pkg-config install rule templates.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1592547 13f79535-47bb-0310-9956-ffa450edef68