build: add rpath to modules that use symbols from libexec_weston

The cms-static, desktop-shell, hmi-controller, ivi-shell, and screen-share
modules use symbols from libexec_weston, e.g.:

  $ ldd /usr/lib/x86_64-linux-gnu/weston/desktop-shell.so | grep "not found"
  	libexec_weston.so.0 => not found

Loading these modules from weston happens to work because the weston executable
itself links against libexec_weston, and has an rpath set. Still, these modules
depend on a library in a non-standard location. Adding an rpath could help
static checkers to make sure all shared objects' dependencies are present.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

ivi-shell/meson.build

@@ -20,7 +20,8 @@ if get_option('shell-ivi')
 		],
 		name_prefix: '',
 		install: true,
-		install_dir: dir_module_weston
+		install_dir: dir_module_weston,
+		install_rpath: '$ORIGIN'
 	)
 	env_modmap += 'ivi-shell.so=@0@;'.format(plugin_shell_ivi.full_path())
 
@@ -42,7 +43,8 @@ if get_option('shell-ivi')
 		],
 		name_prefix: '',
 		install: true,
-		install_dir: dir_module_weston
+		install_dir: dir_module_weston,
+		install_rpath: '$ORIGIN'
 	)
 	env_modmap += 'hmi-controller.so=@0@;'.format(plugin_ivi_hmi.full_path())