cmSystemTools: Revert GetRealPath implementation on Windows

The use of `uv_fs_realpath` introduced by commit v3.11.0-rc1~445^2~1
(cmSystemTools: Implement GetRealPath on Windows, 2017-10-02) causes
`subst` drives to be expanded on Windows, breaking existing use cases.
Revert its use until an alternative implementation can be chosen.

Preserve the behavior introduced by commit v3.11.0-rc1~445^2
(cmTimestamp: For symlinks switch to timestamp of resolved path,
2017-10-02) by retaining use of `uv_fs_realpath` in a function of
a different name.

Fixes: #18033
Issue: #17206

1 files changed, 2 insertions, 1 deletions

diff --git a/Source/cmTimestamp.cxx b/Source/cmTimestamp.cxx
index f1e9283..14cf6e9 100644
--- a/Source/cmTimestamp.cxx
+++ b/Source/cmTimestamp.cxx
@@ -33,7 +33,8 @@ std::string cmTimestamp::FileModificationTime(const char* path,
                                               const std::string& formatString,
                                               bool utcFlag)
 {
-  std::string real_path = cmSystemTools::GetRealPath(path);
+  std::string real_path =
+    cmSystemTools::GetRealPathResolvingWindowsSubst(path);
 
   if (!cmsys::SystemTools::FileExists(real_path)) {
     return std::string();