meson: add build targets for libudev, libsystemd and pkg-config

Mirror install tags with the same names and content

meson.build

@@ -1922,6 +1922,8 @@ subdir('src/udev')
 subdir('src/libudev')
 subdir('src/cryptsetup/cryptsetup-tokens')
 
+alias_target('devel', libsystemd_pc, libudev_pc)
+
 libsystemd = shared_library(
         'systemd',
         disable_mempool_c,
@@ -1940,6 +1942,8 @@ libsystemd = shared_library(
         install_tag: 'libsystemd',
         install_dir : rootlibdir)
 
+alias_target('libsystemd', libsystemd)
+
 install_libsystemd_static = static_library(
         'systemd',
         libsystemd_sources,
@@ -1982,6 +1986,8 @@ libudev = shared_library(
         install_tag: 'libudev',
         install_dir : rootlibdir)
 
+alias_target('libudev', libudev)
+
 install_libudev_static = static_library(
         'udev',
         basic_sources,

src/libsystemd/meson.build

@@ -179,7 +179,7 @@ libsystemd_sym_path = meson.current_source_dir() / 'libsystemd.sym'
 static_libsystemd = get_option('static-libsystemd')
 static_libsystemd_pic = static_libsystemd == 'true' or static_libsystemd == 'pic'
 
-custom_target(
+libsystemd_pc = custom_target(
         'libsystemd.pc',
         input : 'libsystemd.pc.in',
         output : 'libsystemd.pc',

src/libudev/meson.build

@@ -34,7 +34,7 @@ libudev_basic = static_library(
 static_libudev = get_option('static-libudev')
 static_libudev_pic = static_libudev == 'true' or static_libudev == 'pic'
 
-custom_target(
+libudev_pc = custom_target(
         'libudev.pc',
         input : 'libudev.pc.in',
         output : 'libudev.pc',