[ObjCopy] Fix type mismatch in writeCodeSignatureData()

The result of pointer subtraction is of type ptrdiff_t, which is not necessarily the same underlying type as ssize_t. This can lead to a compilation error since std::min requires both parameters to be the same type.

Fixes: llvm#54846

Reviewed By: alexander-shaposhnikov, drodriguez, jhenderson

Differential Revision: https://reviews.llvm.org/D128117

Author: jmroot

llvm/lib/ObjCopy/MachO/MachOWriter.cpp

@@ -520,8 +520,9 @@ void MachOWriter::writeCodeSignatureData() {
   uint8_t *CurrHashWritePosition = HashWriteStart;
   while (CurrHashReadPosition < HashReadEnd) {
     StringRef Block(reinterpret_cast<char *>(CurrHashReadPosition),
-                    std::min(HashReadEnd - CurrHashReadPosition,
-                             static_cast<ssize_t>(CodeSignature.BlockSize)));
+                    std::min(static_cast<size_t>(HashReadEnd
+                             - CurrHashReadPosition),
+                             static_cast<size_t>(CodeSignature.BlockSize)));
     SHA256 Hasher;
     Hasher.update(Block);
     std::array<uint8_t, 32> Hash = Hasher.final();