Fix ASCII detection; can't use "< 0x80" on a signed char.

include/ldap_pvt.h

@@ -106,7 +106,7 @@ LDAP_F (void) ldap_pvt_hex_unescape LDAP_P(( char *s ));
  * these macros assume 'x' is an ASCII x
  * and assume the "C" locale
  */
-#define LDAP_ASCII(c)		((c) < 0x80)
+#define LDAP_ASCII(c)		(!((c) & 0x80))
 #define LDAP_SPACE(c)		((c) == ' ' || (c) == '\t' || (c) == '\n')
 #define LDAP_DIGIT(c)		((c) >= '0' && (c) <= '9')
 #define LDAP_LOWER(c)		((c) >= 'a' && (c) <= 'z')

include/ldap_pvt_uc.h

@@ -77,7 +77,7 @@ LDAP_F (char*) ldap_utf8_strtok( char* sp, const char* sep, char **last);
 /* Optimizations */
 LDAP_V (const char) ldap_utf8_lentab[128];
 
-#define LDAP_UTF8_ISASCII(p) ( *(unsigned char *)(p) ^ 0x80 )
+#define LDAP_UTF8_ISASCII(p) ( !(*(unsigned char *)(p) & 0x80 ) )
 #define LDAP_UTF8_CHARLEN(p) ( LDAP_UTF8_ISASCII(p) \
 	? 1 : ldap_utf8_lentab[*(unsigned char *)(p) ^ 0x80] )
 #define LDAP_UTF8_OFFSET(p) ( LDAP_UTF8_ISASCII(p) \