[fpc-pascal]New optimizer switches meaning

[Jonas Maebe]

Hello,

As of tomorrow, the switches for the optimizer in the snapshot compiler 
will have a slightly different meaning (they will always retain their 
current meaning in 1.0.x, this change is only for 1.1 and later). The new 
meanings are

-O1: stays the same (peephole optimizations only)
-O2: -O1 + common subexpression elimination + register renaming
-O3: repeat the passes from -O2 until no further optimizations are 
possible (or until 5 passes are done, to prevent endless loops)

This means that if you want to enable the "uncertain optimizations" now, 
you always also have to add -Ou. E.g. To get "normal" optimizations, use

-OG2p3

To get maximum optimizations, use

-OG3p3u or -OG3p3ru


Jonas