optimize column width calculation and utf-8 encode for ASCII - st

commit cde480c6939e62771ba3b60ef4eb848031aee9f9
parent 8211e36d281990a39db1853bcd454ac59e53d521
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Sat,  9 May 2020 14:03:14 +0200

optimize column width calculation and utf-8 encode for ASCII

In particular on OpenBSD and on glibc wcwidth() is quite expensive.
On musl there is little difference.

Diffstat:
M st.c  | 2 +-

1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/st.c b/st.c
@@ -2307,7 +2307,7 @@ tputc(Rune u)
     Glyph *gp;
 
     control = ISCONTROL(u);
-    if (!IS_SET(MODE_UTF8 | MODE_SIXEL)) {
+    if (u < 127 || !IS_SET(MODE_UTF8 | MODE_SIXEL)) {
         c[0] = u;
         width = len = 1;
     } else {