dl: add dynamic load module

vlib/dl/dl_windows.c.v

@@ -0,0 +1,18 @@
+module dl
+
+pub const (
+	RTLD_NOW = 0
+	DL_EXT = '.dll'
+)
+
+fn C.LoadLibraryA(libfilename byteptr) voidptr
+fn C.GetProcAddress(handle voidptr, procname byteptr) voidptr
+
+pub fn open(filename string, flags int) voidptr {
+	res := C.LoadLibraryA(filename.str)
+	return res
+}
+
+pub fn sym(handle voidptr, symbol string) voidptr {
+	return C.GetProcAddress(handle, symbol.str)
+}