This adds a HAVE_COMPRESSION macro, which is undefined if neither zlib
nor zstd are present, and is used to no-op compress.h/c. This also has
a side effect of fixing SCons, since it won't define this macro.
Fixes: d7ecbd5bf8 ("util: create some standalone compression helpers")
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9689>
This will be used by the following patch. It allows us to detangle
compression from the disk cache code, and abstract the underlying
compression libraries we use.
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9593>