debug symbols don't work on windows

[andrewrk]

Here's a zig program:

const c = @cImport({
    @cDefine("_NO_CRT_STDIO_INLINE", "1");
    @cInclude("stdio.h");
    @cInclude("string.h");
});

const msg = c"Hello, world!\n";

export fn main(argc: c_int, argv: &&u8) -> c_int {
    if (c.printf(msg) != c_int(c.strlen(msg)))
        return -1;

    @panic("ahhh");
}

When you debug this with MSVC, there is no source code available.

[andrewrk]

Working with Zachary Turner from the LLD team on this issue: https://bugs.llvm.org/show_bug.cgi?id=34910

[andrewrk]

We added uwtable to functions and stack traces are present, still without debug symbols.

However I tested with llvm master branch and this issue is resolved. So this issue will be fixed when we update to use LLVM 6 (release date not yet announced).