[llvm][clang] Fix downstream build failures after edd7fed

Author: jansvoboda11

clang/include/clang/Tooling/DependencyScanning/DependencyScanningCASFilesystem.h

@@ -52,7 +52,7 @@ class DependencyScanningCASFilesystem : public llvm::cas::ThreadSafeFileSystem {
     return FS->setCurrentWorkingDirectory(Path);
   }
   std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override {
+                              SmallVectorImpl<char> &Output) override {
     return FS->getRealPath(Path, Output);
   }
   std::error_code isLocal(const Twine &Path, bool &Result) override {

llvm/lib/CAS/CachingOnDiskFileSystem.cpp

@@ -101,7 +101,7 @@ class CachingOnDiskFileSystemImpl final : public CachingOnDiskFileSystem {
   }
 
   std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const final;
+                              SmallVectorImpl<char> &Output) final;
   ErrorOr<vfs::directory_iterator> getDirectoryIterator(const Twine &Dir);
 
   std::error_code setCurrentWorkingDirectory(const Twine &Path) final;
@@ -455,7 +455,7 @@ CachingOnDiskFileSystemImpl::getDirectoryEntry(const Twine &Path,
 
 std::error_code
 CachingOnDiskFileSystemImpl::getRealPath(const Twine &Path,
-                                         SmallVectorImpl<char> &Output) const {
+                                         SmallVectorImpl<char> &Output) {
   // We can get the real path, but it's not a const operation.
   const vfs::CachedDirectoryEntry *Entry = nullptr;
   if (Error E =

llvm/lib/Support/PrefixMappingFileSystem.cpp

@@ -88,7 +88,7 @@ class PrefixMappingFileSystem final : public ProxyFileSystem {
   }
 
   std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override {
+                              SmallVectorImpl<char> &Output) override {
     PREFIX_MAP_PATH(Path, MappedPath)
     return ProxyFileSystem::getRealPath(MappedPath, Output);
   }