[lld] Fix warning in lld/Macho while building lld for wasm (PR #120889)

[Anutosh Bhat via llvm-commits]

https://github.com/anutosh491 created https://github.com/llvm/llvm-project/pull/120889

While building clang & lld against emscripten for wasm, I see the following 
```
 │ │ /home/runner/work/recipes/recipes/output/bld/rattler-build_llvm_1734801187/work/lld/MachO/SyntheticSections.cpp:2075:25: warning: comparison of integers of
 │ │  different signs: 'long' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
 │ │  2075 |   assert(buf - bufStart == sectionSize &&
 │ │       |          ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~
 │ │ $BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot/include/assert.h:8:28: note: expanded from macro 'assert'
 │ │     8 | #define assert(x) ((void)((x) || (__assert_fail(#x, __FILE__, __LINE__, __func__),0)))
 │ │       |                            ^
 ```
 
 Casting `sectionSize` using `long` should be enough I think

>From b616a99b2452a21aa541226230f823b176a9ead6 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Sun, 22 Dec 2024 17:08:02 +0530
Subject: [PATCH] Fix warning in lld/Macho while building lld for wasm

---
 lld/MachO/SyntheticSections.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
index 28fb8047cacd9a..0806448f921aad 100644
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -2084,7 +2084,7 @@ void ObjCMethListSection::writeTo(uint8_t *bufStart) const {
     uint32_t writtenSize = writeRelativeMethodList(isec, buf);
     buf += writtenSize;
   }
-  assert(buf - bufStart == sectionSize &&
+  assert(buf - bufStart == long(sectionSize) &&
          "Written size does not match expected section size");
 }