libpkgconf: migrate pkgconf client fragment_is_system_dir() to a libpkgconf API

doc/libpkgconf-fragment.rst

@@ -15,6 +15,16 @@ which is composable, mergeable and reorderable.
    :param char* string: The string of text to add as a fragment to the fragment list.
    :return: nothing
 
+.. c:function:: bool pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
+
+   Checks if a `fragment` contains a `system path`.  System paths are detected at compile time and optionally overridden by
+   the ``PKG_CONFIG_SYSTEM_INCLUDE_PATH`` and ``PKG_CONFIG_SYSTEM_LIBRARY_PATH`` environment variables.
+
+   :param pkgconf_client_t* client: The pkgconf client object the fragment belongs to.
+   :param pkgconf_fragment_t* frag: The fragment being checked.
+   :return: true if the fragment contains a system path, else false
+   :rtype: bool
+
 .. c:function:: void pkgconf_fragment_copy(pkgconf_list_t *list, const pkgconf_fragment_t *base, unsigned int flags, bool is_private)
 
    Copies a `fragment` to another `fragment list`, possibly removing a previous copy of the `fragment`

libpkgconf/fragment.c

@@ -238,6 +238,39 @@ pkgconf_fragment_exists(pkgconf_list_t *list, const pkgconf_fragment_t *base, un
 	return pkgconf_fragment_lookup(list, base);
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: bool pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
+ *
+ *    Checks if a `fragment` contains a `system path`.  System paths are detected at compile time and optionally overridden by
+ *    the ``PKG_CONFIG_SYSTEM_INCLUDE_PATH`` and ``PKG_CONFIG_SYSTEM_LIBRARY_PATH`` environment variables.
+ *
+ *    :param pkgconf_client_t* client: The pkgconf client object the fragment belongs to.
+ *    :param pkgconf_fragment_t* frag: The fragment being checked.
+ *    :return: true if the fragment contains a system path, else false
+ *    :rtype: bool
+ */
+bool
+pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
+{
+	const pkgconf_list_t *check_paths = NULL;
+
+	switch (frag->type)
+	{
+	case 'L':
+		check_paths = &client->filter_libdirs;
+		break;
+	case 'I':
+		check_paths = &client->filter_includedirs;
+		break;
+	default:
+		return false;
+	}
+
+	return pkgconf_path_match_list(frag->data, check_paths);
+}
+
 /*
  * !doc
  *

libpkgconf/libpkgconf.h

@@ -235,6 +235,7 @@ void pkgconf_fragment_filter(const pkgconf_client_t *client, pkgconf_list_t *des
 size_t pkgconf_fragment_render_len(const pkgconf_list_t *list);
 void pkgconf_fragment_render_buf(const pkgconf_list_t *list, char *buf, size_t len);
 char *pkgconf_fragment_render(const pkgconf_list_t *list);
+bool pkgconf_fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag);
 
 /* fileio.c */
 char *pkgconf_fgetline(char *line, size_t size, FILE *stream);

main.c

@@ -72,26 +72,6 @@ error_handler(const char *msg, const pkgconf_client_t *client, const void *data)
 	return true;
 }
 
-static bool
-fragment_has_system_dir(const pkgconf_client_t *client, const pkgconf_fragment_t *frag)
-{
-	const pkgconf_list_t *check_paths = NULL;
-
-	switch (frag->type)
-	{
-	case 'L':
-		check_paths = &client->filter_libdirs;
-		break;
-	case 'I':
-		check_paths = &client->filter_includedirs;
-		break;
-	default:
-		return false;
-	}
-
-	return pkgconf_path_match_list(frag->data, check_paths);
-}
-
 static bool
 print_list_entry(const pkgconf_pkg_t *entry, void *data)
 {
@@ -125,7 +105,7 @@ filter_cflags(const pkgconf_client_t *client, const pkgconf_fragment_t *frag, un
 	(void) client;
 	(void) flags;
 
-	if (fragment_has_system_dir(client, frag))
+	if (pkgconf_fragment_has_system_dir(client, frag))
 		return false;
 
 	if (frag->type == 'I')
@@ -143,7 +123,7 @@ filter_libs(const pkgconf_client_t *client, const pkgconf_fragment_t *frag, unsi
 	(void) client;
 	(void) flags;
 
-	if (fragment_has_system_dir(client, frag))
+	if (pkgconf_fragment_has_system_dir(client, frag))
 		return false;
 
 	switch (frag->type)