Roll libc++ from be1c391acca0 to 5abc7f839700 (17 revisions)

Depends on:
* https://chromium-review.googlesource.com/c/chromium/src/+/7821000
* https://chromium-review.googlesource.com/c/chromium/src/+/7822522
* https://webrtc-review.googlesource.com/c/src/+/470620

Ran

    build/modules/modularize/modularize.py --no-cache

to update most BUILD.gn and module.modulemap.in files. Manually
updated buildtools/third_party/libc++/BUILD.gn to look similar.

Ran

    third_party/abseil-cpp/generate_def_files.py

for the (minor) def file updates.

https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxx.git/+log/be1c391acca0..5abc7f839700

2026-05-06 public@kits.net [libcxx][string] Test: fix copy&paste typo for safe_allocator (#195820)
2026-05-05 aidengrossman@google.com [libcxx] Include __utility/exchange.h in thread.h (#195786)
2026-05-05 eiytoq@outlook.com [libc++][mdspan] Fix `mdspan::operator[]` bounds checking and implement LWG4020 (#192269)
2026-05-05 aidengrossman@google.com [libcxx] Remove ASan container overflow checks for SSO strings (#194208)
2026-05-04 cjdb@google.com [libc++] Add `__exchange` as a C++11 utility (#187953)
2026-05-04 nikolasklauser@berlin.de [libc++] Remove libc++'s own fenv.h (#194629)
2026-05-04 nikolasklauser@berlin.de [libc++] Remove libc++'s own ctype.h (#194615)
2026-05-04 nikolasklauser@berlin.de [libc++] Simplify more <random> engines (#195504)
2026-05-04 c8ef@outlook.com [libc++] Implement `ranges::fold_right` (#193997)
2026-05-02 nikolasklauser@berlin.de [libc++] Make __is_seed_sequence a variable template (#195420)
2026-05-02 sharjeelkhan@google.com Update Android CI and Emulator image to API 23 (#194936)
2026-05-01 haowei@google.com [libcxx][lit] Fix dsl.sh.py test failure on Windows (#195230)
2026-05-01 nikolasklauser@berlin.de [libc++][NFC] Simplify the mersenne_twister_engine implementation a bit (#194893)
2026-04-30 nikolasklauser@berlin.de [libc++] Update macOS and AppleClang (#193711)
2026-04-30 nikolasklauser@berlin.de [libc++] Refactor std::print to allow for constant folding of the format part (#185459)
2026-04-30 nikolasklauser@berlin.de [libc++] Remove libc++'s own inttypes.h (#193716)
2026-04-30 nikolasklauser@berlin.de [libc++] Avoid type-punning locale in ios_base (#193507)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/libcxx-chromium
Please CC hans@chromium.org,thakis@chromium.org on the revert to ensure that a human
is aware of the problem.

To file a bug in Chromium: https://bugs.chromium.org/p/chromium/issues/entry

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Bug: 503250165
Compile-Size: libc++ roll
Change-Id: I370861fd0bdd00eade265d6a61834c5c0df6aa66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7821679
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Owners-Override: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Arthur Eubanks <aeubanks@google.com>
Cr-Commit-Position: refs/heads/main@{#1627935}
NOKEYCHECK=True
GitOrigin-RevId: 99ebc432efc6f3a350332b01180e3b3d88e9ec6c