v3.15.0a4
GH-141362: Make `get_externals` handle fetching platform-specific release artifacts (#142405)
GH-140479: Update JIT builds to use LLVM 21 (#140973)
gh-139757: Treat call specially in JIT assembly backend optimizer on x86-64 and AArch64 (GH-142907)
GH-140683: JIT: Improve machine code for loading smaller constants on AArch64. (GH-142511)
JIT: Rename trampoline.c to shim.c (#142974)
gh-138497: Support LLVM_VERSION configuration via env (#138498)
GH-135379: Top of stack caching for the JIT. (GH-135465)
GH-113464: Add a JIT backend for tier 2 (GH-113465)