audio/ardour6: Fix broken 32-bit build

This fixes the Intel 32-bit build.
Modification of the original wscript file is no longer necessary.
Setting mmx and 3dnow compiler flags is not really needed.
Setting 3dnow can even be considered as a bug as this is a AMD only extension.
The build_host_supports_sse flag is only used to throw a warning if the set configuration doesn't match with the build machines configuration.
The warning can be ignored.
The build requires a SSE capable CPU (>=i686) which was also the case in previous versions.

PR: 250206
Submitted by: Michael Beer (maintainer)