Merge branch 'micro' into maint

* micro:
  tests: avoid '$MAKE' redirections, use 'run_make' instead
  tests: avoid use of redirected 'run_make' invocations
  lint: warn against redirected 'run_make' invocations
  comments: next GNU make release 4.0, not 3.83
  tests: fix a potential spurious failure due to global config.site
  HACKING: it's OK to do testsuite refactoring in a micro version

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --cc HACKING
Simple merge

diff --cc maintainer/syntax-checks.mk
Simple merge

diff --cc t/ax/depcomp.sh
Simple merge

diff --cc t/ccnoco3.sh
Simple merge

diff --cc t/check8.sh
Simple merge

diff --cc t/cscope.tap
Simple merge

diff --cc t/libtool9.sh
Simple merge

diff --cc t/ltorder.sh
Simple merge

diff --cc t/silent-c.sh
Simple merge

diff --cc t/silent-lex.sh
Simple merge

diff --cc t/silent-lt.sh
Simple merge

diff --cc t/silent-many-languages.sh
Simple merge

diff --cc t/silent-nested-vars.sh
Simple merge

diff --cc t/silent-yacc.sh
Simple merge