introduce bb_putchar(). saves ~1800 on uclibc (less on glibc).

coreutils/tee.c

@@ -22,6 +22,7 @@ int tee_main(int argc, char **argv)
 	char **names;
 	char **np;
 	char retval;
+//TODO: make unconditional
 #if ENABLE_FEATURE_TEE_USE_BLOCK_IO
 	ssize_t c;
 # define buf bb_common_bufsiz1
@@ -62,7 +63,7 @@ int tee_main(int argc, char **argv)
 	/* names[0] will be filled later */
 
 #if ENABLE_FEATURE_TEE_USE_BLOCK_IO
-	while ((c = safe_read(STDIN_FILENO, buf, BUFSIZ)) > 0) {
+	while ((c = safe_read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
 		fp = files;
 		do
 			fwrite(buf, 1, c, *fp++);