Fix possible typo — double-sufficed make targets, UniMath/Foundations/Preamble.v.vo etc.

[peterlefanulumsdaine]

I was looking over the Makefile’s generated targets (for various reasons), and noticed that it generates some targets/dependencies with double-suffixed file names, e.g. UniMath/Foundations/Preamble.v.vo. In the output of make -pRrq, we find:

UniMath/Foundations/Preamble.v.vo: UniMath/Foundations/Preamble.v.v
#  Implicit rule search has not been done.
#  Modification time never checked.
#  File has not been updated.
#  commands to execute (from `Makefile', line 158):
	ulimit -v unlimited ; /Applications/Xcode.app/Contents/Developer/usr/bin/make -f build/CoqMakefile.make UniMath/Foundations/Preamble.v.vo

Is this intended/correct? I can’t quite figure out what that part of the Makefile is doing, but it looks like this might just be a typo; in that case I think it’s fixed by this PR. But this should certainly be checked by someone who properly understands the Makefile, before merging! After this PR, the generated target above appears as:

UniMath/Foundations/Preamble.vo: UniMath/Foundations/Preamble.v
#  Implicit rule search has not been done.
#  Modification time never checked.
#  File has not been updated.
#  commands to execute (from `Makefile', line 158):
	ulimit -v unlimited ; /Applications/Xcode.app/Contents/Developer/usr/bin/make -f build/CoqMakefile.make UniMath/Foundations/Preamble.vo

In order to troubleshoot this issue, I prepared a branch makefile-debugging with most of the repo deleted — in case it’s of use to others troubleshooting this issue, it’s at https://github.com/peterlefanulumsdaine/UniMath/tree/makefile-debugging

[benediktahrens]

@DanGrayson : could you take a look?

[peterlefanulumsdaine]

It looks by the way like these double-suffixed targets probably first appeared in 0a5f1a4, “add targets for each *.vo file to the Makefile”, in early 2020. It’s perhaps worth noting that now (not sure about then), the *vo files each get another generated target, coming from CoqMakefile.make:

UniMath/Foundations/Preamble.vo: UniMath/Foundations/Preamble.v UniMath/Foundations/Preamble.v UniMath/Foundations/Init.vo | ..coq_makefile_output.d
#  Implicit rule search has not been done.
#  Implicit/static pattern stem: `UniMath/Foundations/Preamble'
#  Modification time never checked.
#  File has not been updated.
#  commands to execute (from `build/CoqMakefile.make', line 815):
	$(SHOW)COQC $<
	$(HIDE)$(TIMER) $(COQC) $(COQDEBUG) $(TIMING_ARG) $(COQFLAGS) $(COQLIBS) $< $(TIMING_EXTRA)

[DanGrayson]

@DanGrayson : could you take a look?

Will do...