Configure: check all DEPEND values against GENERATE, not just .h files

Configure: check all DEPEND values against GENERATE, not just .h files

All files that are given to DEPEND statements in build.info files are
being checked against GENERATE statements, to see if it's reasonable
to look for them in the source tree or not.  This was only done for .h
files, for reasons that are lost in history.  We now change that check
to look at all files instead.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14598)