Trivial speed optimization

* strace.c (tprints): Use fputs_unlocked instead of fputs.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/strace.c b/strace.c
index 1097b0c..34690fc 100644
--- a/strace.c
+++ b/strace.c
@@ -527,7 +527,7 @@
 tprints(const char *str)
 {
 	if (current_tcp) {
-		int n = fputs(str, current_tcp->outf);
+		int n = fputs_unlocked(str, current_tcp->outf);
 		if (n >= 0) {
 			current_tcp->curcol += strlen(str);
 			return;