add --enable-pkg-management configure switch; default=no

Origin commit data
------------------
Commit: fc100fdd44
Author: vanhofen <vanhofen@gmx.de>
Date: 2021-04-11 (Sun, 11 Apr 2021)

Origin message was:
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- add --enable-pkg-management configure switch; default=no

src/gui/update.cpp

@@ -49,7 +49,9 @@
 
 #include <gui/color.h>
 #include <gui/filebrowser.h>
+#if ENABLE_PKG_MANAGEMENT
 #include <gui/opkg_manager.h>
+#endif
 #include <gui/widget/msgbox.h>
 #include <gui/widget/hintbox.h>
 
@@ -494,6 +496,7 @@ bool CFlashUpdate::checkVersion4Update()
 		}
 		hide();
 
+#if ENABLE_PKG_MANAGEMENT
 		//package install:
 		if (file_selected->getType() == CFile::FILE_PKG_PACKAGE){
 			COPKGManager opkg;
@@ -509,6 +512,7 @@ bool CFlashUpdate::checkVersion4Update()
 			//!always leave here!
 			return false;
 		}
+#endif
 
 		//set internal filetype
 		char const * ptr = rindex(filename.c_str(), '.');