Merge branch 'ps/build' into ps/ci-meson

* ps/build: (24 commits)
  Introduce support for the Meson build system
  Documentation: add comparison of build systems
  t: allow overriding build dir
  t: better support for out-of-tree builds
  Documentation: extract script to generate a list of mergetools
  Documentation: teach "cmd-list.perl" about out-of-tree builds
  Documentation: allow sourcing generated includes from separate dir
  Makefile: simplify building of templates
  Makefile: write absolute program path into bin-wrappers
  Makefile: allow "bin-wrappers/" directory to exist
  Makefile: refactor generators to be PWD-independent
  Makefile: extract script to generate gitweb.js
  Makefile: extract script to generate gitweb.cgi
  Makefile: extract script to massage Python scripts
  Makefile: extract script to massage Shell scripts
  Makefile: use "generate-perl.sh" to massage Perl library
  Makefile: extract script to massage Perl scripts
  Makefile: consistently use PERL_PATH
  Makefile: generate doc versions via GIT-VERSION-GEN
  Makefile: generate "git.rc" via GIT-VERSION-GEN
  ...

diff --cc Makefile
Simple merge