Bug 312733 – [libpas] Fix libpas standalone build

• Component: New Bugs
• Status: RESOLVED FIXED

[zak ridouh]

311133@main removed includes from headers whose macro bodies are guarded
by PAS_ENABLE_ISO / PAS_ENABLE_HOTBIT. These macros are 0 in WebKit
(PAS_BMALLOC=1) but 1 in the libpas standalone build, so the includes
were silently required by the standalone build. Restore them inside the
#if PAS_ENABLE_* guards so WebKit keeps the build-speed win.

Also fix several pre-existing issues that surface once the standalone
build gets past the include errors:

- Guard <stdatomic.h> in pas_utils.h for C-only. It conflicts with C++
  <atomic> before C++23 and breaks Verifier.cpp. The macros that use
  atomics (PAS_ATOMIC_TYPE / PAS_ATOMIC_LOAD_RELAXED) only use the
  _Atomic keyword and __c11_atomic_* clang builtins, neither of which
  needs the header.

- Restore <pthread/tsd_private.h> in pas_utils.h. TSDTests.cpp and
  pas_fast_tls.h depend on pthread_key_init_np,
  _pthread_setspecific_direct, and __PTK_FRAMEWORK_* keys from it.

- Add missing bmalloc_iso_allocate_array_by_size and
  bmalloc_try_iso_allocate_array_by_size definitions to
  bmalloc_heap_iso.c. They're declared in bmalloc_heap.h but were lost
  in db6887c9076e when bmalloc_heap.c was split.

- Add 'static' to the 9 PAS_ALWAYS_INLINE functions in pas_mte.h. C99
  inline semantics require an external definition when the compiler
  chooses not to inline (which happens in Debug, where PAS_ALWAYS_INLINE
  drops __attribute__((always_inline))). The codebase convention is
  'static PAS_ALWAYS_INLINE' for header-only inline functions (489
  occurrences across 87 files); the pas_mte.h functions are anomalies.

[Radar WebKit Bug Importer]

<rdar://problem/175129910>

[zak ridouh]

Pull request: https://github.com/WebKit/WebKit/pull/63084

[EWS]

Committed 311770@main (d7b3180cbfe8): <https://commits.webkit.org/311770@main>

Reviewed commits have been landed. Closing PR #63084 and removing active labels.