https://bugs.winehq.org/show_bug.cgi?id=31836
--- Comment #40 from Rafał Mużyło galtgendo@o2.pl ---
I'd probably go with a warning instead of an error, since many distros don't ship 32-bit gstreamer and I don't want to kill those builds because they happen to have 64-bit gstreamer installed.
This is the part we keep misunderstanding each other - I don't see how you could construct such case.
I'd put AC_MSG_ERROR only in case gstreamer is detected, but is mismatched.
If it's not detected, we're not in the branch.
If we're building wine64, gstreamer is detected and mismatch happens, toolchain is incorrect.
If we're building wine32, gstreamer is detected and mismatch happens, toolchain is incorrect.