Makefile: 1.32->1.33

Makefile: 1.32->1.33
main.c: 1.90->1.91
nonints.h: 1.22->1.23
var.c: 1.47->1.48
Author: harti
Log:
Put variable assignments on .MAKEFLAGS and .MFLAGS targets into
the .MAKEFLAGS variable so that these are also passed to sub-makes.
This makes the handling of variables in the command environment more
consistent.

PR:             bin/68853
Submitted by:   Martin Kamerhofer <data@sbox.tugraz.at>

make.1:1.78->1.79
Author: ru
Log:
Document the effects of modifying the .MAKEFLAGS internal
variable and using the .MAKEFLAGS special target, and the
differences between them.

Reviewed by:    harti

Obtained-from: FreeBSD
Submitted-by: Max Okumoto <okumoto@ucsd.edu>
Slightly adjust the change Var_Quote to not cast away a const.