Build failure introduced in feeacd8 with musl C library

[arachsys]

Build failure introduced in feeacd8 with musl C library

[arachsys]

(Might not be crazily risky to be honest: the standard defines them as macros so #undef will always succeed, and the original FILE * values are never touched by shell_manager.cc or anywhere else in Kakoune which sticks to read() and write() on file descriptors rather than buffered IO...)

[krobelus]

I'd prefer stdin_fd to in.

We could probably also get away with #undef stdin though I can see how that might be risky

[arachsys]

I was curious why this worked on glibc, and see that they do

#define stdin stdin
#define stdout stdout
#define stderr stderr

instead. Meanwhile FreeBSD and macOS have

#define	stdin	__stdinp
#define	stdout	__stdoutp
#define	stderr	__stderrp

so I guess they'll be broken too. (Edit: actually they're not broken because the struct members end up declared as UniqueFd __std{in,out,err}p and then accessed like shell.__stdinp.fd, but they're working for an unintended reason!)