Building an rpm from a src rpm

[Steve Buehler]

	Something I have never been able to do from the directions that I have 
found online is to get a source rpm like 
http://download.atrpms.net/production/sources/fedora-3-i386/atrpms/lftp-3.0.13-20.rhfc3.at.src.rpm 
, then open it to get the source files from it, patch a particular file and 
then rebuild it as a non-source rpm to install it.  Can anybody give me 
"Simple" directions for how to do this that even I could understand?  I am 
not a total idiot......most days, but this one has me kind of stumped.  I 
am suppose to run the following "diff" against it to see if it fixes a 
problem that I am having:
-------diff file that I was given follows------
Index: ftpclass.cc
===================================================================
RCS file: /home/lav/cvsroot/lftp/src/ftpclass.cc,v
retrieving revision 1.347
diff -u -p -r1.347 ftpclass.cc
--- ftpclass.cc	21 Jan 2005 14:59:34 -0000	1.347
+++ ftpclass.cc	10 Feb 2005 08:43:28 -0000
@@ -2034,7 +2034,8 @@ int   Ftp::Do()

     case(DATASOCKET_CONNECTING_STATE):
     datasocket_connecting_state:
-      m|=FlushSendQueue();
+      if(pasv_state!=PASV_DATASOCKET_CONNECTING)
+	 m|=FlushSendQueue();
        m|=ReceiveResp();

        if(state!=DATASOCKET_CONNECTING_STATE || Error())
@@ -2103,6 +2104,7 @@ int   Ftp::Do()
  	 }
  	 if(!(res&POLLOUT))
  	    goto usual_return;
+	 DebugPrint("---- ",_("Data connection established"),9);
  	 if(!conn->proxy_is_http)
  	    goto pre_data_open;

-----end of diff file that I was given-----


Thanks
Steve