cross-build: Add comment missing from 9e5b0d9eac
Whilst the commit message documented some of the details, I had intended
to include this comment in the actual header, but failed to amend the
commit properly.
Fixes: 9e5b0d9eac
("cross-build: Fix bmake bootstrap with glibc 2.34")
MFC after: 1 week
This commit is contained in:
parent
03a88e3de9
commit
aee99ab4fe
@ -27,5 +27,21 @@
|
||||
|
||||
#pragma once
|
||||
|
||||
/*
|
||||
* glibc's sys/wait.h and stdlib.h both define various wait-related constants,
|
||||
* depending on __USE_XOPEN(2K8) and if the other header has been included.
|
||||
* Since they each probe the other's include guard to determine that, there is
|
||||
* a window between a header defining its include guard and checking for the
|
||||
* other's within which, if the other is included for the first time, they both
|
||||
* believe the other has already defined the relevant macros etc, and so
|
||||
* neither ends up doing so. This was not previously hit, and is still not hit
|
||||
* when using glibc normally (though seems extremely fragile). However, as of
|
||||
* glibc 2.34, signal.h, included by sys/wait, includes a new bits/sigstksz,
|
||||
* which in turn includes unistd.h (when _SC_SIGSTKSZ_SOURCE is defined, which
|
||||
* is implied by _GNU_SOURCE), which we wrap and include stdlib.h from,
|
||||
* creating the exact aforementioned situation that breaks. Thus, forcefully
|
||||
* include stdlib.h first whenever sys/wait.h is as a workaround, since that
|
||||
* way round still works.
|
||||
*/
|
||||
#include <stdlib.h>
|
||||
#include_next <sys/wait.h>
|
||||
|
Loading…
Reference in New Issue
Block a user