types CHANGE make internal compilation flags public for the extension plugins

Extension plugins perform compilation so they need also to know the
compilation options used by libyang.
diff --git a/src/plugins_exts.h b/src/plugins_exts.h
index 2e90167..2313821 100644
--- a/src/plugins_exts.h
+++ b/src/plugins_exts.h
@@ -54,6 +54,24 @@
  */
 
 /**
+ * @defgroup scflags Schema compile flags
+ * @ingroup schematree
+ *
+ * @{
+ */
+#define LYSC_OPT_RPC_INPUT  LYS_CONFIG_W       /**< Internal option when compiling schema tree of RPC/action input */
+#define LYSC_OPT_RPC_OUTPUT LYS_CONFIG_R       /**< Internal option when compiling schema tree of RPC/action output */
+#define LYSC_OPT_RPC_MASK   LYS_CONFIG_MASK    /**< mask for the internal RPC options */
+#define LYSC_OPT_FREE_SP    0x04               /**< Free the input printable schema */
+#define LYSC_OPT_INTERNAL   0x08               /**< Internal compilation caused by dependency */
+#define LYSC_OPT_NOTIFICATION 0x10             /**< Internal option when compiling schema tree of Notification */
+
+#define LYSC_OPT_GROUPING   0x20               /** Compiling (validation) of a non-instantiated grouping.
+                                                   In this case not all the restrictions are checked since they can be valid only
+                                                   in the real placement of the grouping. TODO - what specifically is not done */
+/** @} scflags */
+
+/**
  * @brief internal context for compilation
  */
 struct lysc_ctx {