Avoid Emacs local variable settings to disable whitespace cleanup,
by creating markup tokens for TAB characters (#TAB#) and space
characters (#SPACE#) (for end-of-line spaces). Modify all the
tests that use TABs to use the new markup. This requires changing
some old-fashioned tests to use the modern run_make_test(). Also
remove some of the comments regarding test numbers now that the
framework keeps track.
I decided this feature was too impacting to make the permanent default
behavior. This set of changes makes the default behavior of make the
old behavior (no second expansion). If you want second expansion, you
must define the .SECONDEXPANSION: special target before the first target
that needs it.
This set of changes ONLY fixes explicit and static pattern rules to work
like this. Implicit rules still have second expansion enabled all the
time: I'll work on that next.
Note that there is still a backward-incompatibility: now to get the old
SysV behavior using $$@ etc. in the prerequisites list you need to set
.SECONDEXPANSION: as well.
Incorporate "order-only" prerequisites patch. Wrote a test for it.
The test shows what might be a bug in the code; I need to look at it
more closely (anyway it doesn't behave as I expected). Also I haven't
done the docs yet.
