replace NOTPARMDECL with TPARM_WORKAROUND

The old logic used a negative check to emit an extern declaration for
tparm(). This guarded against old platforms whose curses implementations
did not declare their own functions.

If there are still any platforms left that need this declaration, they
can set TPARM_WORKAROUND to get the old behavior back.

util/mdgrep.pl

@@ -51,7 +51,7 @@ $specials = {
 # TIMED_DELAY DEF_MAILREADER DEF_PAGER NO_SIGNAL PC_LOCKING LATTICE __GO32__
 # msleep NO_FILE_LINKS bsdi HPUX AMIFLUSH
 # SCREEN_BIOS SCREEN_DJGPPFAST SCREEN_VGA SCREEN_8514
-# EXEPATH NOTSTDC SELECTSAVED NOTPARMDECL
+# EXEPATH NOTSTDC SELECTSAVE
 
 # constants
 @const_true = qw/1 TRUE/;