stage1: implement --omit-lib-prefix

[ifreund]

When building shared libraries for use as plugins, it is often necessary to follow different naming conventions. Passing the new --omit-lib-prefix flag prevents zig from prefixing the name of generated libraries with "lib" and makes following such conventions possible.

Consider this an alternative to #6317
Closes#2231

[ifreund]

I think that even with -femit-bin=foo which is implemented in #6250 this would be worth considering. The advantage to using --omit-lib-prefix over -femit-bin= is that zig is still responsible for determining the proper extension to use based on the target.

[daurnimator]

I think #6317 was the better solution.

[ifreund]

It should be noted that this isn't strictly necessary to solve #2231 as the -femit-bin=foo.so flag introduced has been introduced in #6250. That plus a way to set the flag from the zig build system would allow output to any arbitrary file name.

Still leaving this open as a proposal of sorts.

[andrewrk]

There's also the "soname" to consider here. I think I want to leave this open and solve it in (or shortly after) #6250 because I am trying to merge that branch soon, and I would just have to reimplement this again anyway in the branch.

[Mouvedia]

Is #5861 related?

[andrewrk]

Instead of this, here's how I see this use case being solved:

• -femit-bin=filename
• Use the utility functions of std.Target such as dynamicLibSuffix to create your own filename. Then you have full control over whether to do version numbers, and even whether to override the default and use .so instead of .dylib on macos. Or .a instead of .lib for mingw.

I'll leave #2231 open to track build.zig integration of -femit-bin=foo.

[andrewrk]

Is #5861 related?

@Mouvedia looks like it, thanks for pointing it out 👍