Renamed INITBSS to INIT and INIT to ONCE.

The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name.

Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.

libsrc/pet/mainargs.s

@@ -16,10 +16,10 @@ NAME_LEN = 16                   ; Maximum length of command-name
 
 
 ;---------------------------------------------------------------------------
-; Get possible command-line arguments. Goes into the special INIT segment,
+; Get possible command-line arguments. Goes into the special ONCE segment,
 ; which may be reused after the startup code is run
 
-.segment        "INIT"
+.segment        "ONCE"
 
 .proc   initmainargs
 
@@ -111,7 +111,7 @@ done:   lda     #<argv
 
 .endproc
 
-.segment        "INITBSS"
+.segment        "INIT"
 
 term:   .res    1
 name:   .res    NAME_LEN + 1