Fix IPP/PPD names with period and underscore (Issue #1249)

Author: michaelrsweet

CHANGES.md

@@ -8,6 +8,7 @@ Changes in CUPS v2.4.13 (YYYY-MM-DD)
 - Fixed a memory leak in `httpClose` (Issue #1223)
 - Fixed missing commas in `ippCreateRequestedArray` (Issue #1234)
 - Fixed subscription issues in the scheduler and D-Bus notifier (Issue #1235)
+- Fixed support for IPP/PPD options with periods or underscores (Issue #1249)
 
 
 Changes in CUPS v2.4.12 (2025-04-08)

cups/ppd-cache.c

@@ -5667,7 +5667,7 @@ pwg_unppdize_name(const char *ppd,	/* I - PPD keyword */
 
   for (ptr = name, end = name + namesize - 1; *ppd && ptr < end; ppd ++)
   {
-    if (_cups_isalnum(*ppd))
+    if (_cups_isalnum(*ppd) || *ppd == '.' || *ppd == '_')
     {
       *ptr++ = (char)tolower(*ppd & 255);
       nodash = 0;