glibc destroys[1] the passed pthread_attr_t if pthread_getattr_np()
fails.  Destroying it again leads to a segfault.  Fix it by only
destroying it on success for glibc.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_getattr_np.c;h=ce437205e41dc05653e435f6188768cccdd91c99;hb=HEAD#l205

…ibcs

The calling convention of pthread_getattr_np() is to initialize the
pthread_attr_t, so _destroy() is only necessary on success (and _init()
isn't necessary beforehand).  On the other hand, FreeBSD wants the
attr_t to be initialized before pthread_attr_get_np(), and therefore it
should always be destroyed afterwards.

rust-lang#76828 (comment)

This made too many assumptions about platforms, breaking some things.

Will need to be added later with a better way of gating on proper
alignment, without hardcoding cfg(target_arch)s.

test is already in scope, no need to use the full path

Also add an Oxford comma while we're editing that line.

…n-e0755, r=pickfire,jyn514

Add error explanation for E0755

r? @pickfire

…roy, r=Amanieu

Fix segfault if pthread_getattr_np fails

glibc [destroys][1] the passed pthread_attr_t if pthread_getattr_np()
fails.  Destroying it again leads to a segfault.  Fix it by only
destroying it on success for glibc.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_getattr_np.c;h=ce437205e41dc05653e435f6188768cccdd91c99;hb=HEAD#l205

make replace_prefix only take &str as arguments

included the clippy::manual strip commit to not run into merge conflicts later.

r? @lcnr

…mic-from-mut, r=kodrAus

Revert adding Atomic::from_mut.

This reverts rust-lang#74532, which made too many assumptions about platforms, breaking some things.

Will need to be added later with a better way of gating on proper alignment, without hardcoding cfg(target_arch)s.

---

To be merged if fixing from_mut (rust-lang#76965) takes too long.

r? @ghost

Add a regression test for copy propagation miscompilation

liballoc bench use imported path Bencher

test is already in scope, no need to use the full path

…mulacrum

BTreeMap: extra testing & fixed comments

r? @Mark-Simulacrum

Fix typo in rustc_lexer docs

Also add an Oxford comma while we're editing that line.

Dogfood total_cmp in the test crate

update Miri for another bugfix