New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/23485#discussion_r453222458

Comment:
This is only `nocross` because upstream requires you to generate a man page on the fly using `help2man` and the target executable can't be run on the host. You have two easy fixes to make this cross-compilable:
1. Place a pregenerated `fatsort.1` in the `files` subdirectory alongside the template, then add
```
cp ${FILESDIR}/fatsort.1 man 
```
in either `post_patch` (see comment below) or `pre_build`.

2. Add `build_helper="qemu"` to the template and add the following snippet to `post_patch`:
```
if [ "$CROSS_BUILD}" ]; then
	cat > src/fatsort.qemu <<-EOF
	#!/bin/sh
	qemu-${XBPS_TARGET_QEMU_MACHINE}-static ${wrksrc}/src/fatsort "\$@"
	EOF
	chmod 755 src/fatsort.qemu
	vsed -i man/Makefile -e 's|../src/fatsort|../src/fatsort.qemu|'
fi
```
This will dynamically generate the man page as upstream intends but will use qemu to make it cross-compilable.

Whatever you do, you should also file an issue upstream to get them to ship a pregenerated `fatsort.1` since there is no reason we should be dynamically generating it with every build.