meson: use partial_dependency() to get include directory

Getting the variable directly from pkg-config (without
adding the sysroot prefix) is prone to host contamination
when building in sysroots as the compiler starts looking for the
headers on the host in addition to the sysroot.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>

meson.build

@@ -2618,18 +2618,17 @@ endif
 
 if conf.get('ENABLE_LOCALED') == 1
         if conf.get('HAVE_XKBCOMMON') == 1
-                # logind will load libxkbcommon.so dynamically on its own
-                deps = [libdl]
-                extra_includes = [libxkbcommon.get_pkgconfig_variable('includedir')]
+                # logind will load libxkbcommon.so dynamically on its own, but we still
+                # need to specify where the headers are
+                deps = [libdl, libxkbcommon.partial_dependency(compile_args: true)]
         else
                 deps = []
-                extra_includes = []
         endif
 
         executable(
                 'systemd-localed',
                 systemd_localed_sources,
-                include_directories : includes + extra_includes,
+                include_directories : includes,
                 link_with : [libshared],
                 dependencies : deps,
                 install_rpath : rootlibexecdir,