hw: Include minimal source set in user emulation build

hw: Include minimal source set in user emulation build

Only the files in hwcore_ss[] are required to link a user emulation
binary.

Have meson process the hw/ sub-directories if system emulation is
selected, otherwise directly process hw/core/ to get hwcore_ss[], which
is the only set required by user emulation.

This removes about 10% from the time needed to run
"../configure --disable-system --disable-tools --disable-guest-agent".

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240404194757.9343-8-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240408155330.522792-9-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>