make: default rules for LaTeX -> PDF

[Stephen Gildea]

I would like to see built-in support added to GNU make 3.78.1 for
making PDF files from LaTeX source.

As I see it, this would involve adding the following to the default
list of suffixes:

.PS .pdf

(Note that I use uppercase "PS" to denote a generated PostScript file,
as opposed to "ps" for a source file.)

The following additional variables:

LATEX = latex
DVIPS = dvips
PS2PDF = ps2pdf


And the following default pattern rules:

.dvi.PS:
        $(DVIPS) $(DVIPS_FLAGS) -o $@ $<

.PS.pdf:
        $(PS2PDF) $< $@


And I would like to see the default rule for .tex.dvi changed to use
$(LATEX) instead of $(TEX).