include/devname.h: add missing header

The devname.h requires readproc.h header which has dev_t. Unless
header is included the includes in program files must be in
correct order. I also added FIXME item to remind that for uid &
gid value int not correct data type but uid_t or gid_t from
pwd.h.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

proc/devname.h

@@ -2,6 +2,7 @@
 #define PROC_DEVNAME_H
 
 #include "procps.h"
+#include "readproc.h"
 
 EXTERN_C_BEGIN
 

proc/readproc.h

@@ -141,6 +141,7 @@ typedef struct proc_t {
 	nlwp,		// stat,status     number of threads, or 0 if no clue
 	tgid,		// (special)       thread group ID, the POSIX PID (see also: tid)
 	tty,		// stat            full device number of controlling terminal
+	/* FIXME: int uids & gids should be uid_t or gid_t from pwd.h */
         euid, egid,     // stat(),status   effective
         ruid, rgid,     // status          real
         suid, sgid,     // status          saved