commit cde480c6939e62771ba3b60ef4eb848031aee9f9
from: Hiltjo Posthuma <hiltjo@codemadness.org>
date: Sat May  9 12:11:25 2020 UTC

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.

commit - 8211e36d281990a39db1853bcd454ac59e53d521
commit + cde480c6939e62771ba3b60ef4eb848031aee9f9
blob - 5d4054f619f6646ffe5db2d5768cfbddf6254a2d
blob + 1414f989c4f4c8b6153c57d071dd13a741a54c30
--- st.c
+++ 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 {