musl: meson: add libutmps support

musl only provides fake functions, hence even with -Dutmp=true,
utmp/wtmp functionalities do not work. Let's allow to build with
libutmps.

meson.build

@@ -1028,6 +1028,7 @@ threads = dependency('threads')
 librt = cc.find_library('rt')
 libm = cc.find_library('m')
 libdl = cc.find_library('dl')
+libutmps = dependency('libutmps', required : false)
 
 # On some distributions that use musl (e.g. Alpine), libintl.h may be provided by gettext rather than musl.
 # In that case, we need to explicitly link with libintl.so.

src/login/meson.build

@@ -49,6 +49,7 @@ executables += [
                 'include_directories' : [libexec_template['include_directories'], include_directories('.')],
                 'extract' : systemd_logind_extract_sources,
                 'dependencies' : [
+                        libutmps,
                         threads,
                 ],
         },

src/shared/meson.build

@@ -385,6 +385,7 @@ libshared_deps = [threads,
                   librt,
                   libseccomp_cflags,
                   libselinux_cflags,
+                  libutmps,
                   libxenctrl_cflags,
                   libxz_cflags,
                   libzstd_cflags,

src/test/meson.build

@@ -472,6 +472,7 @@ executables += [
         test_template + {
                 'sources' : files('test-utmp.c'),
                 'conditions' : ['ENABLE_UTMP'],
+                'dependencies' : libutmps,
         },
         test_template + {
                 'sources' : files('test-varlink.c'),