Rename 1992/runme.sh lush.sh and improve it

The script now lets one specify which compiler to use so that one can
(in the case that their cc is clang, for instance like it is with macOS)
specify a path to a real gcc compiler.

1992/lush/README.md

@@ -19,7 +19,7 @@ For more detailed information see [1992 lush in bugs.md](/bugs.md#1992-lush).
 ## To use:
 
 ```sh
-./runme.sh
+./lush.sh
 ```