meson: detect pcre2 dep

meson.build

@@ -1064,6 +1064,17 @@ else
 endif
 conf.set10('HAVE_XKBCOMMON', have)
 
+want_pcre2 = get_option('pcre2')
+if want_pcre2 != 'false'
+        libpcre2 = dependency('libpcre2-8',
+                              required : want_pcre2 == 'true')
+        have = libpcre2.found()
+else
+        have = false
+        libpcre2 = []
+endif
+conf.set10('HAVE_PCRE2', have)
+
 want_glib = get_option('glib')
 if want_glib != 'false'
         libglib =    dependency('glib-2.0',
@@ -2693,6 +2704,7 @@ foreach tuple : [
         ['gnu-efi',          have_gnu_efi],
         ['kmod'],
         ['xkbcommon'],
+        ['pcre2'],
         ['blkid'],
         ['dbus'],
         ['glib'],

meson_options.txt

@@ -260,6 +260,8 @@ option('lz4', type : 'combo', choices : ['auto', 'true', 'false'],
        description : 'lz4 compression support')
 option('xkbcommon', type : 'combo', choices : ['auto', 'true', 'false'],
        description : 'xkbcommon keymap support')
+option('pcre2', type : 'combo', choices : ['auto', 'true', 'false'],
+       description : 'regexp matching support using pcre2')
 option('glib', type : 'combo', choices : ['auto', 'true', 'false'],
        description : 'libglib support (for tests only)')
 option('dbus', type : 'combo', choices : ['auto', 'true', 'false'],

src/basic/build.h

@@ -140,6 +140,12 @@
 #define _IDN_FEATURE_ "-IDN"
 #endif
 
+#if HAVE_PCRE2
+#define _PCRE2_FEATURE_ "+PCRE2"
+#else
+#define _PCRE2_FEATURE_ "-PCRE2"
+#endif
+
 #define _CGROUP_HIEARCHY_ "default-hierarchy=" DEFAULT_HIERARCHY_NAME
 
 #define SYSTEMD_FEATURES                                                \
@@ -163,4 +169,5 @@
         _KMOD_FEATURE_ " "                                              \
         _IDN2_FEATURE_ " "                                              \
         _IDN_FEATURE_ " "                                               \
+        _PCRE2_FEATURE_ " "                                             \
         _CGROUP_HIEARCHY_