Register YANG versioning extension plugins

- Add external declarations for plugins_yang_semver and plugins_yang_revisions
- Register both plugin sets during library initialization
- Add source files to build system (CMakeLists.txt)

Author: jclarke-csco

CMakeLists.txt

@@ -157,6 +157,8 @@ set(libsrc
     src/plugins_exts/yangdata.c
     src/plugins_exts/schema_mount.c
     src/plugins_exts/structure.c
+    src/plugins_exts/yang_semver.c
+    src/plugins_exts/yang_revisions.c
     src/xml.c
     src/xpath.c
     src/validation.c

src/plugins.c

@@ -98,6 +98,8 @@ extern struct lyplg_ext_record plugins_nacm[];
 extern struct lyplg_ext_record plugins_yangdata[];
 extern struct lyplg_ext_record plugins_schema_mount[];
 extern struct lyplg_ext_record plugins_structure[];
+extern struct lyplg_ext_record plugins_yang_semver[];
+extern struct lyplg_ext_record plugins_yang_revisions[];
 
 static pthread_mutex_t plugins_guard = PTHREAD_MUTEX_INITIALIZER;
 
@@ -538,6 +540,8 @@ lyplg_init(ly_bool builtin_type_plugins_only)
         LY_CHECK_GOTO(ret = plugins_insert(NULL, LYPLG_EXTENSION, plugins_yangdata), error);
         LY_CHECK_GOTO(ret = plugins_insert(NULL, LYPLG_EXTENSION, plugins_schema_mount), error);
         LY_CHECK_GOTO(ret = plugins_insert(NULL, LYPLG_EXTENSION, plugins_structure), error);
+        LY_CHECK_GOTO(ret = plugins_insert(NULL, LYPLG_EXTENSION, plugins_yang_semver), error);
+        LY_CHECK_GOTO(ret = plugins_insert(NULL, LYPLG_EXTENSION, plugins_yang_revisions), error);
     }
 
 #ifndef STATIC