Add libminlib for NBSD libc compilation.

This library includes various random and minix-specific functions
included in the Minix libc. Most of them should be part of libsys,
and in general it would be nice to extinguish this library over
time.

lib/nbsd_libminlib/mapdriver.c

@@ -0,0 +1,21 @@
+#include <lib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+PUBLIC int mapdriver(label, major, dev_style, flags)
+char *label;
+int major;
+int dev_style;
+int flags;
+{
+  message m;
+  m.m2_p1 = label;
+  m.m2_l1 = strlen(label);
+  m.m2_i1 = major;
+  m.m2_i2 = dev_style;
+  m.m2_i3 = flags;
+  if (_syscall(VFS_PROC_NR, MAPDRIVER, &m) < 0) return(-1);
+  return(0);
+}
+