- updated the makefiles and code to allow compliation with MinGW once again (some of patch #875485 by perditionc)

- fixed errors and warnings given by gcc


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@3513 212acab6-be3b-0410-9dea-997c60f758d6

Source/exehead/fileform.c

@@ -472,7 +472,7 @@ static int NSISCALL __ensuredata(int amount)
         {
           return -3;
         }
-        r=g_inflate_stream.next_out-_outbuffer;
+        r=(DWORD)g_inflate_stream.next_out-(DWORD)_outbuffer;
         if (r)
         {
           if (!WriteFile(dbd_hFile,_outbuffer,r,&t,NULL) || r != t)