fix minor namespace issues in limits.h

PAGE_SIZE, NZERO, and NL_LANGMAX are XSI-shaded.

include/limits.h

@@ -40,14 +40,10 @@
  || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 
 #define PIPE_BUF 4096
-#ifdef PAGESIZE
-#define PAGE_SIZE PAGESIZE
-#endif
 #define FILESIZEBITS 64
 #define NAME_MAX 255
 #define SYMLINK_MAX 255
 #define PATH_MAX 4096
-#define NZERO 20
 #define NGROUPS_MAX 32
 #define ARG_MAX 131072
 #define IOV_MAX 1024
@@ -82,13 +78,22 @@
 #define RE_DUP_MAX 255
 
 #define NL_ARGMAX 9
-#define NL_LANGMAX 32
 #define NL_MSGMAX 32767
 #define NL_SETMAX 255
 #define NL_TEXTMAX 2048
 
 #endif
 
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) || defined(_XOPEN_SOURCE)
+
+#ifdef PAGESIZE
+#define PAGE_SIZE PAGESIZE
+#endif
+#define NZERO 20
+#define NL_LANGMAX 32
+
+#endif
+
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) \
  || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE+0 < 700)