libyang CHANGE headers includes cleanup using include-what-you-use tool (#1098)

diff --git a/src/plugins_exts.h b/src/plugins_exts.h
index 0b2a5bd..f511710 100644
--- a/src/plugins_exts.h
+++ b/src/plugins_exts.h
@@ -15,8 +15,12 @@
 #ifndef LY_PLUGINS_EXTS_H_
 #define LY_PLUGINS_EXTS_H_
 
-#include "set.h"
+#include "log.h"
 #include "tree_schema.h"
+#include "tree_schema_internal.h"
+
+struct ly_ctx;
+struct lyd_node;
 
 #ifdef __cplusplus
 extern "C" {
@@ -54,44 +58,6 @@
  */
 
 /**
- * @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 {
-    struct ly_ctx *ctx;
-    struct lys_module *mod;
-    struct lys_module *mod_def; /**< context module for the definitions of the nodes being currently
-                                     processed - groupings are supposed to be evaluated in place where
-                                     defined, but its content instances are supposed to be placed into
-                                     the target module (mod) */
-    struct ly_set groupings;    /**< stack for groupings circular check */
-    struct ly_set unres;        /**< to validate leafref's target and xpath of when/must */
-    struct ly_set dflts;        /**< set of incomplete default values */
-    struct ly_set tpdf_chain;
-    uint16_t path_len;
-    int options;                /**< various @ref scflags. */
-#define LYSC_CTX_BUFSIZE 4078
-    char path[LYSC_CTX_BUFSIZE];
-};
-
-/**
  * @brief Possible cardinalities of the YANG statements.
  *
  * Used in extensions plugins to define cardinalities of the extension instance substatements.