[PATCH] elfutils/configure.ac: use $READELF, not readelf

[Mark Wielaard]

Hi Sergei,

On Sun, 2020-06-14 at 20:28 +0100, Sergei Trofimovich wrote:
> Allow user to specify own readelf. Use detected readelf,
> not 'readelf'.

You are absolutely right. We have an explicit AC_CHECK_TOOL for
readelf, so we should use the result whenever we use READELF.

Added ChangeLog entry and pushed to master.

Thanks,

Mark