Trick the meson build system into thinking zig rc is rc.exe

When determining the type of RC compiler, meson passes `/?` or `--version` and then reads from `stdout` looking for particular string(s) anywhere in the output.

So, by adding the string "Microsoft Resource Compiler" to the `/?` output, meson will recognize `zig rc` as rc.exe and give it the correct options, which works fine since `zig rc` is drop-in CLI compatible with rc.exe.

This allows using `zig rc` with meson for (cross-)compiling, by either:

- Setting WINDRES="zig rc" or putting windres = ['zig', 'rc'] in the cross-file
  + This will work like rc.exe, so it will output .res files. This will only link successfully if you are using a linker that can do .res -> .obj conversion (so something like zig cc, MSVC, lld)
- Setting WINDRES="zig rc /:output-format coff" or putting windres = ['zig', 'rc', '/:output-format', 'coff'] in the cross-file
  + This will make meson pass flags as if it were rc.exe, but it will cause the resulting .res file to actually be a COFF object file, meaning it will work with any linker that handles COFF object files

Example cross file that uses `zig cc` (which can link `.res` files, so `/:output-format coff` is not necessary) and `zig rc`:

```
[binaries]
c = ['zig', 'cc', '--target=x86_64-windows-gnu']
windres = ['zig', 'rc']

[target_machine]
system = 'windows'
cpu_family = 'x86_64'
cpu = 'x86_64'
endian = 'little'
```

Author: squeek502

lib/compiler/resinator/cli.zig

@@ -17,6 +17,7 @@ pub const usage_string_after_command_name =
     \\This is necessary when the input path begins with a forward slash.
     \\
     \\Supported option prefixes are /, -, and --, so e.g. /h, -h, and --h all work.
+    \\Drop-in compatible with the Microsoft Resource Compiler.
     \\
     \\Supported Win32 RC Options:
     \\  /?, /h                  Print this help and exit.

lib/compiler/resinator/main.zig

@@ -81,7 +81,8 @@ pub fn main() !void {
     defer options.deinit();
 
     if (options.print_help_and_exit) {
-        try cli.writeUsage(stderr.writer(), "zig rc");
+        const stdout = std.io.getStdOut();
+        try cli.writeUsage(stdout.writer(), "zig rc");
         return;
     }