PHP: Fix infinite loop reading an identifier ending at EOF

Bit-wise operation is inappropriate here because `c` might be negative,
since EOF is generally represented as -1.  Since -1 is stored as all
bits at 1 on most common architectures, the test will evaluate to true,
hence entering an infinite loop.

tagmanager/ctags/php.c

@@ -498,7 +498,7 @@ static void addToScope (tokenInfo *const token, const vString *const extra)
 
 static boolean isIdentChar (const int c)
 {
-	return (isalnum (c) || c == '_' || c & 0x80);
+	return (isalnum (c) || c == '_' || c >= 0x80);
 }
 
 static int skipToCharacter (const int c)