library: build on non-glibc systems

Some non-glibc systems didn't have libio.h or __BEGIN_DECLS
Changes to make it more standard.

References:
 issue #88

NEWS

@@ -3,6 +3,7 @@ procps-ng-3.3.14
   * pgrep: Don't segfault on non match                     Debian #894917
   * pgrep/pkill: Revert so matches all namespaces          issue #91
   * free: Fix scaling on 32-bit systems                    issue #89
+  * library: Build on non-glibc systems                    issue #88
 
 procps-ng-3.3.13
 ----------------

proc/numa.h

@@ -20,9 +20,9 @@
 #ifndef PROCPS_NUMA_H
 #define PROCPS_NUMA_H
 
-#include <features.h>
+#include "procps.h"
 
-__BEGIN_DECLS
+EXTERN_C_BEGIN
 
 void numa_init (void);
 void numa_uninit (void);
@@ -30,6 +30,6 @@ void numa_uninit (void);
 extern int (*numa_max_node) (void);
 extern int (*numa_node_of_cpu) (int);
 
-__END_DECLS
+EXTERN_C_END
 
 #endif

procio.c

@@ -24,7 +24,6 @@
 #endif
 #include <errno.h>
 #include <fcntl.h>
-#include <libio.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>