fix VkFlags64 bitmasks

Setup/src/Program.bf

@@ -270,15 +270,25 @@ class EnumFeature : VulkanFeature
 			lastCaseName = enumcase.name;
 		}
 		str.Append("\t// pretty names\n");
-		StringView prefix = name;
+		String prefix = scope .(name);
 		for (let t in tags)
 		{
 			if (!prefix.EndsWith(t)) continue;
-			prefix.RemoveFromEnd(t.Length);
+			prefix.Length -= t.Length;
 			break;
 		}
-		if (prefix.EndsWith("FlagBits"))
-			prefix.RemoveFromEnd(8);
+		{
+			char8 digit = '\0';
+			if (prefix[^1].IsDigit)
+			{
+				digit = prefix[^1];
+				prefix.Length--;
+			}
+			if (prefix.EndsWith("FlagBits"))
+				prefix.Length -= 8;
+			if (digit != '\0')
+				prefix.Append(digit);
+		}
 		String lastName = scope .(128);
 		for (let enumcase in cases)
 		{
@@ -331,6 +341,7 @@ class EnumFeature : VulkanFeature
 					str.Remove(index, strI);
 				}
 				str.Append(tag);
+				if (str[index] == '_') str.Remove(index);
 				if (str[index].IsDigit) str.Insert(index, '_');
 			}
 
@@ -598,6 +609,8 @@ class RegistryParser : XmlParser
 				case "bitmask":
 					strBuf.Set("typealias ");
 					bitmask_requires.Set(atts.GetValueOrDefault("requires"));
+					if (bitmask_requires.IsEmpty)
+						bitmask_requires.Set(atts.GetValueOrDefault("bitvalues"));
 					eStack.Add(.Type_Bitmask);
 				case "basetype":
 					strBuf.Clear();