Move e_pid and e_pgid to libprocess, Add get_self_pid () syscall

libprocess/process_self.c

@@ -0,0 +1,22 @@
+#include <process_self.h>
+#include <system.h>
+
+static int e_pid;
+static int e_pgid;
+static int pid;
+static int pgid;
+
+void libprocess_self_init (void) {
+  e_pid = get_exec_pid ();
+  e_pgid = get_procgroup (e_pid);
+  pid = get_self_pid ();
+  pgid = get_procgroup (pid);
+}
+
+int process_get_exec_pid (void) { return e_pid; }
+
+int process_get_exec_pgid (void) { return e_pgid; }
+
+int process_get_pid (void) { return pid; }
+
+int process_get_pgid (void) { return pgid; }

libprocess/process_self.h

@@ -0,0 +1,14 @@
+#ifndef _LIBPROCESS_PROCESS_SELF_H
+#define _LIBPROCESS_PROCESS_SELF_H
+
+void libprocess_self_init (void);
+
+int process_get_exec_pid (void);
+
+int process_get_exec_pgid (void);
+
+int process_get_pid (void);
+
+int process_get_pgid (void);
+
+#endif // _LIBPROCESS_PROCESS_SELF_H

libprocess/src.mk

@@ -1,5 +1,7 @@
 include $(platform)/src.mk
 
-c += process.c
+c += process.c \
+		 process_self.c
 
-o += process.o
+o += process.o \
+		 process_self.o