[lld] [lld-macho] Find objects in library search path (PR #78628)

[via llvm-commits]

https://github.com/OldWorldOrdr created https://github.com/llvm/llvm-project/pull/78628

Find object files in library search path just like Apple's linker, this makes building with some older MacOS SDKs easier since clang runs with `-lcrt1.10.6.o`

>From e73fc2d0263e9e601f2964a90cfe347e8d2bb87c Mon Sep 17 00:00:00 2001
From: OldWorldOrdr <joey.t.reinhart at gmail.com>
Date: Thu, 18 Jan 2024 16:20:52 -0500
Subject: [PATCH] [lld-macho] Find objects in library search path

---
 lld/MachO/Driver.cpp | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
index 401459a054394ec..f04165f5c026153 100644
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -95,11 +95,16 @@ static std::optional<StringRef> findLibrary(StringRef name) {
               findPathCombination("lib" + name, config->librarySearchPaths,
                                   {".tbd", ".dylib", ".so"}))
         return path;
-      return findPathCombination("lib" + name, config->librarySearchPaths,
-                                 {".a"});
+      else if (std::optional<StringRef> path = findPathCombination(
+                   "lib" + name, config->librarySearchPaths, {".a"}))
+        return path;
+      return findPathCombination(name, config->librarySearchPaths, {""});
     }
-    return findPathCombination("lib" + name, config->librarySearchPaths,
-                               {".tbd", ".dylib", ".so", ".a"});
+    if (std::optional<StringRef> path =
+            findPathCombination("lib" + name, config->librarySearchPaths,
+                                {".tbd", ".dylib", ".so", ".a"}))
+      return path;
+    return findPathCombination(name, config->librarySearchPaths, {""});
   };
 
   std::optional<StringRef> path = doFind();