fix RLIMIT_ constants for mips

The mips arch is special in that it uses different RLIMIT_
numbers than other archs, so allow bits/resource.h to override
the default RLIMIT_ numbers (empty on all archs except mips).
Reported by orc.

arch/mips/bits/resource.h

@@ -0,0 +1,5 @@
+#define RLIMIT_NOFILE  5
+#define RLIMIT_AS      6
+#define RLIMIT_RSS     7
+#define RLIMIT_NPROC   8
+#define RLIMIT_MEMLOCK 9

include/sys/resource.h

@@ -15,6 +15,7 @@ extern "C" {
 #endif
 
 #include <bits/alltypes.h>
+#include <bits/resource.h>
 
 typedef unsigned long long rlim_t;
 
@@ -78,11 +79,13 @@ int prlimit(pid_t, int, const struct rlimit *, struct rlimit *);
 #define RLIMIT_DATA    2
 #define RLIMIT_STACK   3
 #define RLIMIT_CORE    4
+#ifndef RLIMIT_RSS
 #define RLIMIT_RSS     5
-#define RLIMIT_NOFILE  7
-#define RLIMIT_AS      9
 #define RLIMIT_NPROC   6
+#define RLIMIT_NOFILE  7
 #define RLIMIT_MEMLOCK 8
+#define RLIMIT_AS      9
+#endif
 #define RLIMIT_LOCKS   10
 #define RLIMIT_SIGPENDING 11
 #define RLIMIT_MSGQUEUE 12