[lld] [lld][MachO] Support for -interposable (PR #131813)

[John Holdsworth via llvm-commits]

johnno1962 wrote:

Modifying the linking to force the platform version:
```
# RUN: ~/D2/Xcode162.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot ~/D2/Xcode162.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -fuse-ld=~/Developer/llvm-project/build/bin/ld64.lld -Xlinker -interposable -lSystem -o %t/main2 %t/main.o %t/2.o %t/3.o
```
Yields:
```
Mac-minii:llvm-project$ objdump -d ./build/tools/lld/test/MachO/Output/interposable.s.tmp/main2 

./build/tools/lld/test/MachO/Output/interposable.s.tmp/main2:	file format mach-o 64-bit x86-64

Disassembly of section __TEXT,__text:

00000001000003a0 <_main>:
1000003a0: c3                          	retq

00000001000003a1 <my_func>:
1000003a1: c3                          	retq

00000001000003a2 <my_user>:
1000003a2: e8 07 00 00 00              	callq	0x1000003ae <dyld_stub_binder+0x1000003ae>
1000003a7: c3                          	retq

Disassembly of section __TEXT,__stubs:

00000001000003a8 <__stubs>:
1000003a8: ff 25 52 0c 00 00           	jmpq	*0xc52(%rip)            ## 0x100001000 <dyld_stub_binder+0x100001000>
1000003ae: ff 25 54 0c 00 00           	jmpq	*0xc54(%rip)            ## 0x100001008 <dyld_stub_binder+0x100001008>
```
But how to force the platform version for lld directly in an llvm specific test?

https://github.com/llvm/llvm-project/pull/131813