libsys: various updates

- move system calls for use by services from libminlib into libsys;
- move srv_fork(2) and srv_kill(2) from RS and into libsys;
- replace getprocnr(2) with sef_self(3);
- rename previous getnprocnr(2) to getprocnr(2);
- clean up getepinfo(2);
- change all libsys calls that used _syscall to use _taskcall, so as
  to avoid going through errno to pass errors; this is already how
  most calls work anyway, and many of the calls previously using
  _syscall were already assumed to return the actual error;
- initialize request messages to zero, for future compatibility
  (note that this does not include PCI calls, which are in need of a
  much bigger overhaul, nor kernel calls);
- clean up more of dead DS code as a side effect.

Change-Id: I8788f54c68598fcf58e23486e270c2d749780ebb

lib/libsys/vm_map_phys.c

@@ -1,35 +1,36 @@
-#define _SYSTEM 1
-#include <lib.h>
+#include "syslib.h"
+
 #include <sys/mman.h>
-#include <minix/syslib.h>
 #include <minix/vm.h>
 #include <stdarg.h>
 #include <string.h>
-#include <errno.h>
 
-void *vm_map_phys(endpoint_t who, void *phaddr, size_t len)
+void *
+vm_map_phys(endpoint_t who, void *phaddr, size_t len)
 {
 	message m;
 	int r;
 
+	memset(&m, 0, sizeof(m));
 	m.VMMP_EP = who;
 	m.VMMP_PHADDR = phaddr;
 	m.VMMP_LEN = len;
 
 	r = _taskcall(VM_PROC_NR, VM_MAP_PHYS, &m);
 
-	if(r != OK) return MAP_FAILED;
+	if (r != OK) return MAP_FAILED;
 
 	return (void *) m.VMMP_VADDR_REPLY;
 }
 
-int vm_unmap_phys(endpoint_t who, void *vaddr, size_t len)
+int
+vm_unmap_phys(endpoint_t who, void *vaddr, size_t len)
 {
 	message m;
 
+	memset(&m, 0, sizeof(m));
 	m.VMUP_EP = who;
 	m.VMUP_VADDR = vaddr;
 
 	return _taskcall(VM_PROC_NR, VM_UNMAP_PHYS, &m);
 }
-