* m4/header.m4 (AM_CONFIG_HEADER): Rename to ...
(_AM_CONFIG_HEADERS): ... this.
(_AM_CONFIG_HEADER_INSINUATE): Define AC_CONFIG_HEADERS to
call _AM_CONFIG_HEADERS; and AM_CONFIG_HEADER to call
AC_CONFIG_HEADERS.
* automake.in (scan_autoconf_traces): Trace AC_CONFIG_HEADERS
instead of AM_CONFIG_HEADER.
* tests/autoheader2.test: New file.
* tests/Makefile.am (TESTS): Add autoheader2.test.
Suggested by Raja R Harinath.