Added request at13457 from harbu.

plugins/include/amxconst.inc

@@ -260,3 +260,5 @@ enum {
 #define AMX_FLAG_LINEOPS	(1<<5)   /* line ops are parsed by the JIT [loadtime only flag] */
 #define AMX_FLAG_BROWSE		(1<<14)   /* browsing/relocating or executing */
 #define AMX_FLAG_RELOC		(1<<15)   /* jump/call addresses relocated */
+
+#define INVALID_PLUGIN_ID	-1	

plugins/include/amxmodx.inc

@@ -677,4 +677,7 @@ native require_module(const module[]);
 native is_amd64_server();
 
 /* Returns 0 on success, like the POSIX specification */
-native mkdir(const dirname[]);
+native mkdir(const dirname[]);
+
+/* Returns plugin id searched by file/name.  Returns INVALID_PLUGIN_ID on failure. */
+native find_plugin_byfile(const filename[], ignoreCase=1);