meson: Cleanup include-dir paths, use base path without repetitions

Avoid setting the subdir all the times, just use the global definition
plus the specific module subdir

gio/meson.build

@@ -9,6 +9,8 @@ gio_c_args_internal = [
   '-DGIO_COMPILATION',
 ]
 
+gio_includedir = glib_includedir / 'gio'
+
 # FIXME: Install empty glib_giomodulesdir
 
 gnetworking_h_conf = configuration_data()
@@ -169,7 +171,7 @@ gnetworking_h_conf.set('NAMESER_COMPAT_INCLUDE', gnetworking_h_nameser_compat_in
 
 gnetworking_h = configure_file(input : 'gnetworking.h.in',
                                output : 'gnetworking.h',
-                               install_dir : join_paths(get_option('includedir'), 'glib-2.0/gio'),
+                               install_dir : gio_includedir,
                                configuration : gnetworking_h_conf)
 
 gdbus_headers = files(
@@ -747,7 +749,7 @@ gvisibility_h = custom_target(
   output: 'gio-visibility.h',
   command: [gen_visibility_macros, meson.project_version(), 'visibility-macros', 'GIO', '@OUTPUT@'],
   install: true,
-  install_dir: glib_includedir / 'gio',
+  install_dir: gio_includedir,
   install_tag : 'devel',
 )
 gio_sources += gvisibility_h
@@ -755,7 +757,7 @@ gio_sources += gvisibility_h
 gio_headers += application_headers
 gio_headers += settings_headers
 gio_headers += gdbus_headers
-install_headers(gio_headers, subdir : 'glib-2.0/gio/')
+install_headers(gio_headers, install_dir : gio_includedir)
 
 # We can't use gnome.mkenums() because the GNOME module looks for glib-mkenums
 # in PATH, which means you can't bootstrap glib with its own glib-mkenums.
@@ -764,7 +766,7 @@ gioenumtypes_h = custom_target('gioenumtypes_h',
   capture : true,
   input : gio_headers,
   install : true,
-  install_dir : join_paths(get_option('includedir'), 'glib-2.0/gio'),
+  install_dir : gio_includedir,
   command : [python, glib_mkenums,
              '--template', files('gioenumtypes.h.template'),
              '@INPUT@', gnetworking_h])

glib/meson.build

@@ -1,4 +1,5 @@
 glib_sources = []
+glib_sub_includedir = glib_includedir / 'glib'
 
 glibconfig_h = configure_file(input : 'glibconfig.h.in', output : 'glibconfig.h',
   install_dir : join_paths(get_option('libdir'), 'glib-2.0/include'),
@@ -19,7 +20,7 @@ gvisibility_h = custom_target(
   output: 'glib-visibility.h',
   command: [gen_visibility_macros, meson.project_version(), 'visibility-macros', 'GLIB', '@OUTPUT@'],
   install: true,
-  install_dir: glib_includedir / 'glib',
+  install_dir: glib_sub_includedir,
   install_tag : 'devel',
 )
 
@@ -146,7 +147,7 @@ glib_headers = files(
   'glib-unix.h',
   'glib-object.h',
 )
-install_headers(glib_headers, subdir : 'glib-2.0')
+install_headers(glib_headers, install_dir : glib_includedir)
 
 # Expose as variable to be used by gobject-introspection
 # when it includes GLib as a subproject
@@ -160,7 +161,8 @@ glib_deprecated_headers = files(
   'deprecated/grel.h',
   'deprecated/gthread.h',
 )
-install_headers(glib_deprecated_headers, subdir : 'glib-2.0/glib/deprecated')
+install_headers(glib_deprecated_headers,
+  install_dir : glib_sub_includedir / 'deprecated')
 
 glib_sub_headers = files(
   'glib-autocleanups.h',
@@ -243,7 +245,7 @@ glib_sub_headers = files(
   'gprintf.h',
 )
 
-install_headers(glib_sub_headers, subdir : 'glib-2.0/glib')
+install_headers(glib_sub_headers, install_dir : glib_sub_includedir)
 
 deprecated_sources = files(
   'deprecated/gallocator.c',

gmodule/meson.build

@@ -6,6 +6,8 @@ g_module_have_dlerror = 0
 
 g_module_impl = ''
 
+g_module_includedir = glib_includedir / 'gmodule'
+
 # On Windows force native WIN32 shared lib loader
 if host_system == 'windows'
   g_module_impl = 'G_MODULE_IMPL_WIN32'
@@ -64,13 +66,13 @@ gmoduleconf_h = configure_file(input : 'gmoduleconf.h.in',
 gmodule_h = files('gmodule.h')
 gmodule_c = files('gmodule.c')
 
-install_headers([gmodule_h], subdir : 'glib-2.0')
+install_headers([gmodule_h], install_dir : glib_includedir)
 
 gvisibility_h = custom_target(
   output: 'gmodule-visibility.h',
   command: [gen_visibility_macros, meson.project_version(), 'visibility-macros', 'GMODULE', '@OUTPUT@'],
   install: true,
-  install_dir: glib_includedir / 'gmodule',
+  install_dir: g_module_includedir,
   install_tag : 'devel',
 )
 

gobject/meson.build

@@ -1,3 +1,5 @@
+gobject_includedir = glib_includedir / 'gobject'
+
 gobject_install_headers = files(
   'gobject-autocleanups.h',
   'glib-types.h',
@@ -29,12 +31,12 @@ gvisibility_h = custom_target(
   output: 'gobject-visibility.h',
   command: [gen_visibility_macros, meson.project_version(), 'visibility-macros', 'GOBJECT', '@OUTPUT@'],
   install: true,
-  install_dir: glib_includedir / 'gobject',
+  install_dir: gobject_includedir,
   install_tag : 'devel',
 )
 gobject_sources += gvisibility_h
 
-install_headers(gobject_install_headers, subdir : 'glib-2.0/gobject')
+install_headers(gobject_install_headers, install_dir : gobject_includedir)
 
 gobject_sources += files(
   'gatomicarray.c',

meson.build

@@ -83,7 +83,7 @@ glib_libdir = join_paths(glib_prefix, get_option('libdir'))
 glib_libexecdir = join_paths(glib_prefix, get_option('libexecdir'))
 glib_datadir = join_paths(glib_prefix, get_option('datadir'))
 glib_pkgdatadir = join_paths(glib_datadir, 'glib-2.0')
-glib_includedir = join_paths(glib_prefix, get_option('includedir'))
+glib_includedir = join_paths(glib_prefix, get_option('includedir'), 'glib-2.0')
 if get_option('gio_module_dir') != ''
   glib_giomodulesdir = join_paths(glib_prefix, get_option('gio_module_dir'))
 else
@@ -2364,7 +2364,7 @@ install_data('m4macros/glib-2.0.m4', 'm4macros/glib-gettext.m4', 'm4macros/gsett
 configure_file(output : 'config.h', configuration : glib_conf)
 
 if host_system == 'windows'
-  install_headers([ 'msvc_recommended_pragmas.h' ], subdir : 'glib-2.0')
+  install_headers([ 'msvc_recommended_pragmas.h' ], install_dir : glib_includedir)
 endif
 
 if get_option('man')