meson: Allow for libdir and includedir to be absolute paths

Meson allows to use absolute paths for libdir and includedir [0]. But if
they're absolute paths one must not append the prefix. The join_paths()
function [1] nicely supports both relative and absolute paths.

This is e.g. important for Nixpkgs (i.e. Nix(OS)) where binaries and
library files are usually installed under different prefixes.

[0]: mesonbuild/meson@a513bcf
[1]: https://mesonbuild.com/Reference-manual.html#join_paths

Signed-off-by: Michael Weiss <[email protected]>

Author: primeos

meson.build

@@ -65,7 +65,7 @@ libva_lt_version = '@0@.@1@.@2@'.format(libva_lt_current,
 
 driverdir = get_option('driverdir')
 if driverdir == ''
-  driverdir = '@0@/@1@/@2@'.format(get_option('prefix'), get_option('libdir'), 'dri')
+  driverdir = join_paths(get_option('prefix'), get_option('libdir'), 'dri')
 endif
 
 configinc = include_directories('.')

pkgconfig/meson.build

@@ -2,8 +2,8 @@ pkgconf = configuration_data()
 
 pkgconf.set('prefix', get_option('prefix'))
 pkgconf.set('exec_prefix', '${prefix}')
-pkgconf.set('libdir', '${prefix}/@0@'.format(get_option('libdir')))
-pkgconf.set('includedir', '${prefix}/@0@'.format(get_option('includedir')))
+pkgconf.set('libdir', join_paths(get_option('prefix'), get_option('libdir')))
+pkgconf.set('includedir', join_paths(get_option('prefix'), get_option('includedir')))
 pkgconf.set('LIBVA_VERSION', libva_version)
 pkgconf.set('VA_API_VERSION', va_api_version)
 pkgconf.set('LIBVA_DRIVERS_PATH', driverdir)