Hello,
I found a few issues with the WRITECOPY patch after wine-staging commit ae46f56f2cf20585387ff61cb7b36fd5f3d84837 which I managed to pretty much fix
Patch 0003 is a replacement for the previous 0003 patch (apparently very early signal handling is still needed for some Unix-side ntdll functions); the added early argument checks could be replaced with NtCurrentTeb() instead (this would lead to 2 identical signal_init_process() calls though which may look weird)
Patch 0004 updates the previous 0004 patch by removing a forgotten i386 compile-time check (which didn't make sense after that wine-staging commit)
Patch 0005 is updated to fix conflicts because of the patch 0004 update (so it can be ignored for a manual rebase)
Patch 0010 enables the WRITECOPY stuff by default (this is effectively a replacement for patches 0010 and 0011 without their hacky logic which really only works for Chromium-based applications); if this patch addition is too radical, then at least patches 0010 and 0011 should definitely be removed (hopefully there won't be another patch race anytime soon)
Please note that patch 0003 also adds an extra ntdll-Syscall_Emulation dependency to fix a bad interaction with that patchset (also I should've sent this email at least a day earlier but hopefully some of these patches can get pushed)
Thanks