rust: scalpel.dylib is not built with the right cflags / -arch flags

[ryandesign (Ryan Carsten Schmidt)]

The rust portfile creates a helper dylib using this command:

            system "${configure.cc} -dynamiclib -exported_symbols_list ${export_list_file} -o ${scalpel_dylib} ${prefix}/lib/libcxx/libc++.a"

I don't see MacPorts cflags in there, including -arch flags, so this will prevent a universal build from being possible.

Granted, this block only takes effect on older systems, and the port already indicates that it only supports arm64 and x86_64, so on older x86_64 systems there is no opportunity to build universal anyway. Yet, it is still proper procedure to specify the correct -arch flags and cflags with every compilation. Who knows, maybe one day we can return i386 support to the portfile to fix the librsvg headache; at that time at the latest building this lib for the right archs will be important.

[catap (Kirill A. Korinsky)]

Ryan, this library is used on old system to fill missed symbols to allow run precompiled rust to build the rust.

To be honest: rust has a lot of issues and I doubt that universal build for it is possible at all.

[ryandesign (Ryan Carsten Schmidt)]

An x86_64/i386 universal build of rust used to be possible before rust was updated to a version that dropped i386 support.

If you're not interested in the universal aspect, then consider the user who wishes to configure a MacPorts installation for cross compilation by changing build_arch in macports.conf. MacPorts allows this, but what this portfile does doesn't accommodate that.

[catap (Kirill A. Korinsky)]

Ryan, I'm interesting and trying to make universal port at M1.

I just would like to point that it doesn't work right now.

I'll add suggested flags.

[catap (Kirill A. Korinsky)]

In 5fc1fec717f6d409901360f4337bbc531f932945/macports-ports (master):

rust: build scalpel.dylib from sources

Closes: #64127