Merge branch 'maint'

* maint:
  NEWS: document deprecation of 'shar' and 'compress' dist formats
  m4: rename minuso.m4 -> prog-cc-c-o.m4
  tests: adjust or remove some obsolete comments
  tests: remove some useless 'unset' of variables
  tests: avoid a couple of extra sleep with GNU make
  NEWS: document testsuite work for 1.13.3
  lint: remove a couple of obsolete syntax checks
  lint: cosmetics: use #-comments, not ##-comments
  lint: cosmetics: some reordering
  lint: recipes of syntax check require GNU grep; ensure it is used
  lint: better name for a syntax check
  tests: rename $am_make_rc_got -> $am_make_rc
  tests: some tests make no sense if "$CC -c -o" doesn't work
  AM_PROG_CC_C_O: don't rely on AC_PROG_CC_C_O, re-implement similar logic
  compile: rewrite AC_PROG_CC with AM_PROG_CC_C_O contents
  tests: ensure $required is not set too late

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

diff --cc NEWS
Simple merge

diff --cc m4/Makefile.inc
index ac7067df7dba9b645f13cd60005d902338bf9e41,8df18907456d317d32adf4d10d324c5f4b269e45..73b8865e52c4f9e77dbd332aa51f8954f8be037d
--- 1/m4/Makefile.inc
--- 2/m4/Makefile.inc
+++ b/m4/Makefile.inc
@@@ -40,8 -41,8 +40,7 @@@ dist_automake_ac_DATA = 
    %D%/lispdir.m4 \
    %D%/maintainer.m4 \
    %D%/make.m4 \
-   %D%/minuso.m4 \
    %D%/missing.m4 \
 -  %D%/mkdirp.m4 \
    %D%/obsolete.m4 \
    %D%/options.m4 \
    %D%/python.m4 \

diff --cc m4/init.m4
Simple merge

diff --cc maintainer/syntax-checks.mk
index 9191757a1d117f8437e6478dbdde858fa6fd0007,5d08750dabc110bfdcdf956b6f50f689be6ed128..7da29d172546d7a8d4ade1d92b1a18d4f3483132
--- 1/maintainer/syntax-checks.mk
--- 2/maintainer/syntax-checks.mk
+++ b/maintainer/syntax-checks.mk
@@@ -80,11 -78,35 +78,35 @@@ sc_unquoted_DESTDIR 
  sc_tabs_in_texi \
  sc_at_in_texi
  
- ## These check avoids accidental configure substitutions in the source.
- ## There are exactly 7 lines that should be modified from automake.in to
- ## automake, and 9 lines that should be modified from aclocal.in to
- ## aclocal.
+ $(syntax_check_rules): bin/automake bin/aclocal
+ maintainer-check: $(syntax_check_rules)
+ .PHONY: maintainer-check $(syntax_check_rules)
+ 
+ # Check that the list of tests given in the Makefile is equal to the
+ # list of all test scripts in the Automake testsuite.
+ maintainer-check: maintainer-check-list-of-tests
+ 
+ # I'm a lazy typist.
+ lint: maintainer-check
+ .PHONY: lint
+ 
+ # The recipes of syntax checks require a modern GNU grep.
+ sc_sanity_gnu_grep:
+       $(AM_V_GEN)grep --version | grep 'GNU grep' >/dev/null 2>&1 \
+         && ab=$$(printf 'a\nb') \
+         && test "$$(printf 'xa\nb\nc' | grep -Pzo 'a\nb')" = "$$ab" \
+         || { \
+           echo "Syntax checks recipes require a modern GNU grep" >&2; \
+           exit 1; \
+         }
+ .PHONY: sc_sanity_gnu_grep
+ $(syntax_check_rules): sc_sanity_gnu_grep
+ 
+ # These check avoids accidental configure substitutions in the source.
 -# There are exactly 8 lines that should be modified from automake.in to
++# There are exactly 7 lines that should be modified from automake.in to
+ # automake, and 9 lines that should be modified from aclocal.in to
+ # aclocal.
 -automake_diff_no = 8
 +automake_diff_no = 7
  aclocal_diff_no = 9
  sc_diff_automake sc_diff_aclocal: in=$($*_in)
  sc_diff_automake sc_diff_aclocal: out=$($*_script)
@@@ -443,12 -443,16 +443,12 @@@ sc_m4_am_plain_egrep_fgrep
          exit 1; \
        fi
  
- ## Use 'configure.ac', not the obsolete 'configure.in', as the name
- ## for configure input files in our testsuite.  The latter  has been
- ## deprecated for several years (at least since autoconf 2.50) and
- ## support for it will be removed in Automake 1.14.
 -# Prefer 'configure.ac' over the obsolescent 'configure.in' as the name
++# Use 'configure.ac', not the obsolete 'configure.in', as the name
+ # for configure input files in our testsuite.  The latter  has been
 -# deprecated for several years (at least since autoconf 2.50).
++# deprecated for several years (at least since autoconf 2.50) and
++# support for it will be removed in Automake 2.0.
  sc_tests_no_configure_in:
 -      @if grep -E '\bconfigure\\*\.in\b' $(xtests) $(xdefs) \
 -            | grep -Ev '/backcompat.*\.(sh|tap):' \
 -            | grep -Ev '/autodist-configure-no-subdir\.sh:' \
 -            | grep -Ev '/(configure|help)\.sh:' \
 -            | grep .; \
 -      then \
 +      @if grep -E '\bconfigure\\*\.in\b' $(xtests) $(xdefs); then \
          echo "Use 'configure.ac', not 'configure.in', as the name" >&2; \
          echo "for configure input files in the test cases above." >&2; \
          exit 1; \

diff --cc t/list-of-tests.mk
Simple merge

diff --cc t/subpkg.sh
Simple merge