Implement __isOSVersionAtLeast and __isPlatformVersionAtLeast

Author: madsmtm

README.md

@@ -178,6 +178,11 @@ These builtins are needed to support 128-bit integers.
 - [x] udivmodti4.c
 - [x] udivti3.c
 - [x] umodti3.c
+- [ ] os_version_check.c
+   - [x] `__isOSVersionAtLeast` (Darwin)
+   - [x] `__isPlatformVersionAtLeast` (Darwin)
+   - [ ] `__isPlatformOrVariantPlatformVersionAtLeast` (macOS)
+   - [ ] `__isOSVersionAtLeast` (Android)
 
 These builtins are needed to support `f16` and `f128`, which are in the process
 of being added to Rust.
@@ -410,7 +415,6 @@ Miscellaneous functionality that is not used by Rust.
 - ~~i386/fp_mode.c~~
 - ~~int_util.c~~
 - ~~loongarch/fp_mode.c~~
-- ~~os_version_check.c~~
 - ~~riscv/fp_mode.c~~
 - ~~riscv/restore.S~~ (callee-saved registers)
 - ~~riscv/save.S~~ (callee-saved registers)

src/lib.rs

@@ -43,6 +43,7 @@ pub mod float;
 pub mod int;
 pub mod math;
 pub mod mem;
+pub mod os_version_check;
 
 // `libm` expects its `support` module to be available in the crate root. This config can be
 // cleaned up once `libm` is made always available.