Your earlier posts indicate that you are running a 64-bit Slackware. If you have wine installed I assume that you also installed the Slackware multilib packages.
If you want to compile a 32-bit program (for using it with the 32-bit Wine) then first you need to have installed the 32-bit versions of the dependencies, which in case of wineasio means that you need the 32-bit "compat32" version of jack-audio-connection-kit.
In order to compile a 32-bit program on Slackware64 multilib, you start with "sourcing" the /etc/profile.d/32dev/sh script (note that there is a dot at the start of the line):
Then compile a 32-bit version of jack-audio-connection-kit by running the jack-audio-connection-kit.SlackBuild script:
Next, convert the resulting package to a "compat32" package and install that:
convertpkg-compat32 -i /tmp/jack-audio-connection-kit-0.121.3-i486-*.t?z
upgradepkg --install-new /tmp/jack-audio-connection-kit-compat32-0.121.3-*.t?z
And then proceed with compiling a wineasio package. I think that will work now.