Add more missing config.h #includes

Now that we use AC_SYS_LARGEFILE, we need to pull in config.h at least
whereever we use mmap().  Fixes at least the test-suite and simple-shm
on 32 bit systems.
diff --git a/clients/simple-touch.c b/clients/simple-touch.c
index 26a9d24..69e460c 100644
--- a/clients/simple-touch.c
+++ b/clients/simple-touch.c
@@ -21,6 +21,8 @@
  * OF THIS SOFTWARE.
  */
 
+#include <config.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>