suggestion/draft: add "strip" option for zig build

[nikkicoon]

Zig Version

0.12.0

Steps to Reproduce and Observed Behavior

As discussed a little earlier (as far as I remember, #14420), in NetBSD we sometimes omit debug symbols under some conditions.
A package we have in pkgsrc, passphrase (https://codeberg.org/owl/passphrase/src/branch/trunk/build.zig), provides this working option:

pub fn build(b: *std.Build) !void {
... snip ...
    const exe = b.addExecutable(.{
... snip ...
        .strip = b.option(
            bool,
            "strip",
            "Omit debug symbols",
        ) orelse (optimize != .Debug),
    });

Since this is something zig can do, I think this ought to be something zig provides by default to keep the patches to build.zig files to a minimum.

I'm guessing this won't be enough, am I missing something: master...nikkicoon:zig:build/strip

Used in pkgsrc like this (mk code fragment snippet):

.if ${ZIGSTRIP:Uyes:M[yY][eE][sS]}
.  if ${MKDEBUG:Uyes:M[yY][eE][sS]} && ${INSTALL_UNSTRIPPED:Uyes:tl} == yes
ZIGBUILDARGS+=		-Dstrip=true
.  endif
.endif