watchman: multiple dependents failing for 10.14 and earlier: invalid output constraint '=@ccc' in asm

[mascguy (Christopher Nielsen)]

Various dependencies of watchman are all failing to build on 10.14 and earlier, due to asm-related errors like the following:

error: invalid output constraint '=@ccc' in asm

Based on local testing, all can be fixed by blacklisting Clang versions prior to 11:

compiler.blacklist-append \
                    {clang < 1100}

The list of ports that need to be fixed are:

• fizz
• fbthrift
• fb303
• wangle
• watchman

[danchr (Dan Villiom Podlaski Christiansen)]

The correct fix for this to use a newer Clang from MacPorts, right? Is there a standard way of picking the version?

[mascguy (Christopher Nielsen)]

Replying to danchr:

The correct fix for this to use a newer Clang from MacPorts, right? Is there a standard way of picking the version?

Since the port compiles fine with Clang 11 on 10.15, I'd suggest the following. Just tested in my 10.14 VM, and this resolves the issue:

compiler.blacklist-append \
                    {clang < 1100}

Also remember to add portgroup for compiler_blacklist_versions.

On a related note, it looks like wangle has the same issue. So we'll want to apply the same fix there too.

[mascguy (Christopher Nielsen)]

Add another port to the list needing the same fix: fbthrift.

FYI, I'm working through the dependency list, to get watchman working on macOS releases earlier than 10.15. And the latter may also be on the list, I'll find out momentarily.