Add meson.build files to build with meson

Provide both build systems in parallel for now, to ensure that we work
out all the differences between the two. Some time from now, we'll give
up on autotools.

Meson tends to be faster and probably easier to read/maintain. On my
machine, the full meson configure+build+install takes a little under
half as long as a similar autotools-based invocation.

Building with meson is a two step process. First, configure the build:

  meson build

Then, compile the project:

  ninja -C build

There's some mild differences in functionality between meson and
autotools.  specifically:

1) No singular update-po target. meson only generates individual
update-po targets for each textdomain (of which we have 3).  To make
this easier, there's a build-aux/update-po script which finds all
update-po targets and runs them.

2) No 'make dist' equivalent. Just run 'git archive' to generate a
suitable tarball for distribution.

1 files changed, 61 insertions, 0 deletions

diff --git a/meson_options.txt b/meson_options.txt
new file mode 100644
index 00000000..422a9ae4
--- /dev/null
+++ b/meson_options.txt
@@ -0,0 +1,61 @@
+# build behavior
+option('use-git-version', type : 'boolean', value : false,
+       description : 'take version information from git')
+option('buildstatic', type : 'boolean', value : false,
+       description : 'if true, build staticly linked binaries')
+
+# directories and filenames
+option('root-dir', type : 'string', value : '/',
+       description : 'set the location of the root operating directory')
+
+option('pkg-ext', type : 'string', value : '.pkg.tar.gz',
+       description : 'set the file extension used by packages')
+
+option('src-ext', type : 'string', value : '.src.tar.gz',
+       description : 'set the file extension used by source packages')
+
+option('scriptlet-shell', type : 'string', value : '/bin/sh',
+       description : 'The full path of the shell used to run install scriptlets')
+
+option('ldconfig', type : 'string', value : '/sbin/ldconfig',
+       description : 'set the full path to ldconfig')
+
+option('buildscript', type : 'string', value : 'PKGBUILD',
+       description : 'set the build script name used by makepkg')
+
+option('datarootdir', type : 'string', value : 'share',
+       description : 'FIXME')
+
+option('makepkg-template-dir', type : 'string', value : '/usr/share/makepkg-template',
+       description : 'template dir used by makepkg-template')
+
+option('debug-suffix', type : 'string', value : 'debug',
+       description : 'suffix for split debugging symbol packages used by makepkg')
+
+# dependencies, features
+option('doc', type : 'feature', value : 'auto',
+       description : 'generate docs and manpages')
+
+option('doxygen', type : 'feature', value : 'disabled',
+       description : 'generate doxygen manpages and html')
+
+option('curl', type : 'feature', value : 'auto',
+       description : 'use curl to download files')
+
+option('crypto', type : 'combo', choices : ['openssl', 'nettle'],
+       description : 'select crypto implementation')
+
+option('gpgme', type : 'feature', value : 'auto',
+       description : 'use GPGME for PGP signature verification')
+option('gpgme-libdir', type : 'string', value : '/usr/lib',
+       description : 'search directory for gpgme libraries.')
+
+option('i18n', type : 'boolean', value : true,
+       description : 'enable localization of pacman, libalpm and scripts')
+
+# tools
+option('duflags', type : 'string', value : 'autodetect',
+       description : 'flags to pass to du to measure file size')
+
+option('sedinplaceflags', type : 'string', value : 'auto',
+       description : 'flags to pass to sed to edit a file in-place')