If we know that index is larger than SSO size, we know that we can't be
in SSO case, and should access the pointer. This removes extra check
from operator[] for inputs known at compile time to be larger than SSO.

This applies clang-format to the std::string unit tests in preparation
for landing https://reviews.llvm.org/D140550.

Differential Revision: https://reviews.llvm.org/D140612

First, fix a collision with the Point type from MacTypes.h, which was
reported on Slack, 2022-07-31: https://cpplang.slack.com/archives/C2X659D1B/p1659284691275889

Second, rename the meta:: namespace to types::. OSX's "/usr/include/ncurses.h"
defines a `meta` function, and is (for some reason) included in
"<SDK>/usr/include/module.modulemap", so that identifier is off-limits
for us to use in anything that compiles with -fmodules:

    libcxx/test/support/type_algorithms.h:16:11: error: redefinition of 'meta' as different kind of symbol
    namespace meta {
               ^
    <SDK>/usr/include/ncurses.h:603:28: note: previous definition is here
    extern NCURSES_EXPORT(int) meta (WINDOW *,bool);                        /* implemented */
                                ^

Finally, add a CI configuration for modules on OS X to make sure it
does not regress.

Differential Revision: https://reviews.llvm.org/D144915

We currently call a lot of functions with the same list of types. To avoid forgetting any of them, this patch adds type_lists and utilities for it. Specifically, it adds
- `type_list` - This is just a list of types
- `concatenate` - This allows concatenating type_lists
- `for_each` - Iterate over a type_list

Reviewed By: ldionne, #libc

Spies: jloser, EricWF, libcxx-commits

Differential Revision: https://reviews.llvm.org/D137476

Reviewed By: ldionne, #libc, huixie90

Spies: huixie90, libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D131856

This patch switches the build compiler for AIX from ibm-clang to clang. ibm-clang++_r has `-pthread` by default, but clang for AIX doesn't, so `-pthread` had to be added to the test config. A bunch of tests now pass, so the `XFAIL` was removed. This patch also switch the build to use the visibility support available in clang-15 to control symbols exported by the shared library (AIX traditionally uses explicit export lists for this purpose).

Reviewed By: #libc, #libc_abi, daltenty, #libunwind, ldionne

Differential Revision: https://reviews.llvm.org/D127470

Reviewed By: #libc, ldionne

Spies: daltenty, sdasgup3, ldionne, arichardson, MTC, ChuanqiXu, mehdi_amini, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, stephenneuendorffer, Joonsoo, grosul1, Kayjukh, jurahul, msifontes, tatianashp, rdzhabarov, teijeong, cota, dcaballe, Chia-hungDuan, wrengr, wenzhicui, arphaman, Mordante, miscco, Quuxplusone, smeenai, libcxx-commits

Differential Revision: https://reviews.llvm.org/D110598

Reviewed By: ldionne, #libc

Spies: libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D119123

Also, some tests had multiple death tests in them, so split them into
separate tests instead. The second death test would obviously never
get run, because the first one would kill the program before.

These tests were only being run when _LIBCPP_DEBUG was defined, which
isn't the case by default when we run the test suite. In other words,
all these debug mode tests were never being run. This commit makes sure
they are run, and in some cases, extracts them into a file under test/libcxx
to separate them from the Standard tests.

Differential Revision: https://reviews.llvm.org/D88836