add 2 files

[cbh34680]

I executed the following on Rocky9 Linux.

./gnulib-tool --create-megatestdir --with-tests --dir=$HOME/my/gnulib-bin error-h

I received the following error message

executing aclocal -I glm4
executing autoconf
configure:4438: error: possibly undefined macro: gl_CHECK_NEXT_HEADERS
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.

To resolve this, I added two lines to the file "modules/error-h".

[pixelb]

please forward this to bug-gnulib@gnu.org thank you