build: simplify include_directories

Define common_inc which includes both public_inc and the project root directory.
The project root directory will allow access to config.h and all the shared/
headers.

Replacing all custom '.', '..', '../..', '../shared' etc. include paths with
common_inc reduces clutter in the target definitions and enforces the common
 #include directive style, as e.g. including shared/ headers without the
subdirectory name no longer works.

Unfortunately this does not prevent one from using private libweston headers
with the usual include pattern for public headers.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

libweston/backend-drm/meson.build

@@ -9,7 +9,7 @@ lib_backlight = static_library(
 		dep_libdrm_headers,
 		dependency('libudev')
 	],
-	include_directories: include_directories('../..'),
+	include_directories: common_inc,
 	install: false
 )
 dep_backlight = declare_dependency(
@@ -84,7 +84,7 @@ endif
 plugin_drm = shared_library(
 	'drm-backend',
 	srcs_drm,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_drm,
 	name_prefix: '',
 	install: true,

libweston/backend-fbdev/meson.build

@@ -19,7 +19,7 @@ deps_fbdev = [
 plugin_fbdev = shared_library(
 	'fbdev-backend',
 	srcs_fbdev,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_fbdev,
 	name_prefix: '',
 	install: true,

libweston/backend-headless/meson.build

@@ -11,7 +11,7 @@ srcs_headless = [
 plugin_headless = shared_library(
 	'headless-backend',
 	srcs_headless,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: dep_libweston,
 	name_prefix: '',
 	install: true,

libweston/backend-rdp/meson.build

@@ -28,7 +28,7 @@ deps_rdp = [
 plugin_rdp = shared_library(
 	'rdp-backend',
 	'rdp.c',
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_rdp,
 	name_prefix: '',
 	install: true,

libweston/backend-wayland/meson.build

@@ -33,7 +33,7 @@ endif
 plugin_wlwl = shared_library(
 	'wayland-backend',
 	srcs_wlwl,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_wlwl,
 	name_prefix: '',
 	install: true,

libweston/backend-x11/meson.build

@@ -46,7 +46,7 @@ endif
 plugin_x11 = shared_library(
 	'x11-backend',
 	srcs_x11,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_x11,
 	name_prefix: '',
 	install: true,

libweston/meson.build

@@ -75,7 +75,7 @@ endif
 lib_weston = shared_library(
 	'weston-@0@'.format(libweston_major),
 	srcs_libweston,
-	include_directories: [ include_directories('..', '../shared'), public_inc ],
+	include_directories: common_inc,
 	install: true,
 	version: '0.0.@0@'.format(libweston_revision),
 	link_whole: lib_libshared,
@@ -167,7 +167,7 @@ endif
 lib_session_helper = static_library(
 	'session-helper',
 	srcs_session_helper,
-	include_directories: include_directories('..', '../shared'),
+	include_directories: common_inc,
 	dependencies: deps_session_helper,
 	install: false
 )
@@ -185,7 +185,7 @@ lib_libinput_backend = static_library(
 		dep_libinput,
 		dependency('libudev', version: '>= 136')
 	],
-	include_directories: include_directories('..'),
+	include_directories: common_inc,
 	install: false
 )
 dep_libinput_backend = declare_dependency(
@@ -209,7 +209,7 @@ if get_option('weston-launch')
 		'weston-launch',
 		'weston-launch.c',
 		dependencies: [dep_pam, systemd_dep, dep_libdrm],
-		include_directories: include_directories('..'),
+		include_directories: common_inc,
 		install: true
 	)
 

libweston/renderer-gl/meson.build

@@ -29,7 +29,7 @@ endforeach
 plugin_gl = shared_library(
 	'gl-renderer',
 	srcs_renderer_gl,
-	include_directories: include_directories('../..', '../../shared'),
+	include_directories: common_inc,
 	dependencies: deps_renderer_gl,
 	name_prefix: '',
 	install: true,