* meson.build: Install `freetype2.m4`.

Fixes #1290.

meson.build

diff --git a/meson.build b/meson.build
index 12a319f..bedf132 100644
--- a/meson.build
+++ b/meson.build
@@ -54,6 +54,9 @@
 
 ft2_defines = []
 
+freetype_aclocaldir = join_paths(get_option('datadir'), 'aclocal')
+
+
 # Generate a custom `ftmodule.h` version based on the content of
 # `modules.cfg`.
 
@@ -433,6 +436,10 @@
   install_dir: join_paths(freetype_includedir, 'freetype/config'))
 
 
+install_data('builds/unix/freetype2.m4',
+  install_dir: freetype_aclocaldir)
+
+
 pkgconfig = import('pkgconfig')
 
 pkgconfig.generate(ft2_lib,