FYI, now I'm looking at the changes induced by the following:
git ls-files | grep '\.m4$' | xargs perl -pi \
-e 's/(AC_[A-Z_]+\()([^[()]+?)([,)])/$1\[$2]$3/g;' \
-e 's/(AC_[A-Z_]+\((?:\[[^,]+?\], ){1})([^,[()]+?)([,)])/$1\[$2]$3/g;' \
-e 's/(AC_[A-Z_]+\((?:\[[^,]+?\], ){2})([^,[()]+?)([,)])/$1\[$2]$3/g;' \
-e 's/(AC_[A-Z_]+\((?:\[[^,]+?\], ){3})([^,[()]+?)([,)])/$1\[$2]$3/g'
# [note that the above is not equivalent to using {0,3} ]
# This is the sole unwanted change (to onceonly.m4):
# -# AC_CHECK_DECLS([DECL1], [DECL2], ...).
# +# AC_CHECK_DECLS([DECL1], [DECL2], [...]).
# Undo it:
perl -pi -e 's/\[\.\.\.\]/.../' m4/onceonly.m4
FYI, adding the 4-arg transform induced only two new changes,
both in comments:
+# _AC_FUNC_FNMATCH_IF([STANDARD = GNU | POSIX], [CACHE_VAR], [IF-TRUE],
[IF-FALSE])
+dnl AC_LIB_HAVE_LINKFLAGS([name], [dependencies], [includes], [testcode])
