remove no-longer-needed Makefile hackery

Makefile

@@ -12,11 +12,9 @@ clean: Makefile.coq
 	rm -f Makefile.coq
 .PHONY: clean
 
-# Create Coq Makefile. POSIX awk can't do in-place editing, but coq_makefile wants the real
-# filename, so we do some file gymnastics.
+# Create Coq Makefile.
 Makefile.coq: _CoqProject Makefile awk.Makefile
 	"$(COQBIN)coq_makefile" -f _CoqProject -o Makefile.coq
-	mv Makefile.coq Makefile.coq.tmp && awk -f awk.Makefile Makefile.coq.tmp > Makefile.coq && rm Makefile.coq.tmp
 
 # Install build-dependencies
 build-dep/opam: opam Makefile

awk.Makefile

-# awk program that patches the Makefile generated by Coq.
-
-# Detect the name this project will be installed under.
-/\$\(COQLIBINSTALL\)\/.*\/\$\$i/ {
-# Wow, POSIX awk is really broken.  I mean, isn't it supposed to be a text processing language?
-# And there is not even a way to access the matched groups of a regexp...?!? Lucky enough,
-# we can just split the string at '/' here.
-	split($0, PIECES, /\//);
-	PROJECT=PIECES[2];
-}
-
-# Patch the uninstall target to work properly, and to also uninstall stale files.
-# Also see <https://coq.inria.fr/bugs/show_bug.cgi?id=4907>.
-# This (and the section above) can be removed once we no longer support Coq 8.6.
-/^uninstall: / {
-	print "uninstall:";
-	print "\tif [ -d \"$(DSTROOT)\"$(COQLIBINSTALL)/"PROJECT"/ ]; then find \"$(DSTROOT)\"$(COQLIBINSTALL)/"PROJECT"/ \\( -name \"*.vo\" -o -name \"*.v\" -o -name \"*.glob\" -o \\( -type d -empty \\) \\) -print -delete; fi";
-	getline;
-	next
-}
-
-# This forwards all unchanged lines
-1