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

diff --git a/coreutils/id.c b/coreutils/id.c
index 1cc8c4d..536e946 100644
--- a/coreutils/id.c
+++ b/coreutils/id.c
@@ -102,7 +102,7 @@
 	/* Print full info like GNU id */
 	/* bb_getpwuid(0) doesn't exit on failure (returns NULL) */
 	status = printf_full(uid, bb_getpwuid(NULL, 0, uid), 'u');
-	putchar(' ');
+	bb_putchar(' ');
 	status |= printf_full(gid, bb_getgrgid(NULL, 0, gid), 'g');
 
 #if ENABLE_SELINUX
@@ -121,6 +121,6 @@
 	}
 #endif
 
-	putchar('\n');
+	bb_putchar('\n');
 	fflush_stdout_and_exit(status);
 }