Fix sysinstall/conf.c assuming <stdint.h> is indirectly included.

sysinstall/conf.c

@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>