Lazbuild crashes when loading a invalid environment (patch in uploaded files)

Original Reporter info from Mantis: corpsman @corpsman

• Reporter name: Uwe Schächterle

Description:

When Loading a not supported Environment the typecast

OldActiveDesktop := TDesktopOpt(FDesktops.Find(OldActiveDesktopName));

crashes

this could be fixed by the patch i attached.

Steps to reproduce:

on my system everytime i run lazbuild this happens

Additional information:

at first i installed Lazarus
then i deleted everything expect the fpc folder
then i did a checkout into the lazarus folder and hit make

=> maybe this left some strange / invalid environment settings, that leed lazbuid to crash

Mantis conversion info:

• Mantis ID: 38376
• Build: 64405
• Platform: All
• Version: 2.0.10
• Fixed in revision: r64414 (#5ee798bb)