library: sysstat and vmstat api changes

Use the standard libc declarations.
For protecting the headers for C++ procps used to have its
own defines, this change makes them use the standard libc ones.

getstat() -> procps_stat_*
vminfo() -> procps_vmstat_*
These two components of the library now use the newer version of
the API with less exposed global variables. The old methods are
there for now.

Signed-off-by: Craig Small <csmall@enc.com.au>

proc/pwcache.h

@@ -2,9 +2,9 @@
 #define PROCPS_PROC_PWCACHE_H
 
 #include <sys/types.h>
-#include "procps.h"
+#include <proc/procps.h>
 
-EXTERN_C_BEGIN
+__BEGIN_DECLS
 
 // used in pwcache and in readproc to set size of username or groupname
 #define P_G_SZ 33
@@ -12,6 +12,6 @@ EXTERN_C_BEGIN
 extern char *user_from_uid(uid_t uid);
 extern char *group_from_gid(gid_t gid);
 
-EXTERN_C_END
+__END_DECLS
 
 #endif