mlton on 10.6 x86_64 tries to build for 32 bit (and fails on linking)

[barracuda156]

See: ​https://build.macports.org/builders/ports-10.6_x86_64-builder/builds/174948/steps/install-port/logs/stdio

[ryandesign (Ryan Carsten Schmidt)]

Indeed, it is using the -m32 flag, which is probably a result of the erroneous assumption that the output of uname -m is the desired userland architecture. On macOS, it's the kernel architecture, and on some x86_64 machines running Mac OS X 10.6 the kernel is 32-bit, which is of course not a problem at all for running 64-bit userland programs.

​https://github.com/MLton/mlton/blob/92137753df8c003e0628bf10a676eef492fe47b3/bin/platform#L73-L75
​https://github.com/MLton/mlton/blob/92137753df8c003e0628bf10a676eef492fe47b3/bin/platform#L146-L148
​https://github.com/MLton/mlton/blob/92137753df8c003e0628bf10a676eef492fe47b3/runtime/Makefile#L105-L107

While that's a bug that could be reported upstream if they care to fix their assumptions about ancient versions of macOS, for MacPorts we should fix the Portfile so that it does not allow the build system to make assumptions; MacPorts should dictate to the build system what architecture to build for, since the user may wish to override it by setting build_arch in macports.conf.

[barracuda156]

Replying to ryandesign:

Yeah, I can just add a conditional fix for x86_64. The issue was mentioned to upstream, the response: ​https://github.com/MLton/mlton/issues/502#issuecomment-1650010095

[barracuda156]

In 425ca72f0905176d0bdf17d2d8d4131e02924a2d/macports-ports (master):

mlton: update to 20240119, fix older Intel builds

Fixes: #68488
Closes: #40022