[lld/mac] Prefix errors with "ld64.lld" instead of just "lld"

Matches the ELF and COFF ports, which use ld.lld and lld-link, respectively.

While here, also move up `cleanupCallback` to match ELF / COFF.

Differential Revision: https://reviews.llvm.org/D97715

GitOrigin-RevId: bacacb9d5c979b2c32ef76ac00acfa445187028f
diff --git a/MachO/Driver.cpp b/MachO/Driver.cpp
index c5ae0ae..d3e675c 100644
--- a/MachO/Driver.cpp
+++ b/MachO/Driver.cpp
@@ -712,10 +712,12 @@
   lld::stdoutOS = &stdoutOS;
   lld::stderrOS = &stderrOS;
 
+  errorHandler().cleanupCallback = []() { freeArena(); };
+
+  errorHandler().logName = args::getFilenameWithoutExe(argsArr[0]);
   stderrOS.enable_colors(stderrOS.has_colors());
   // TODO: Set up error handler properly, e.g. the errorLimitExceededMsg
 
-  errorHandler().cleanupCallback = []() { freeArena(); };
 
   MachOOptTable parser;
   opt::InputArgList args = parser.parse(argsArr.slice(1));