1 files changed, 22 insertions, 11 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 6b88a03..028952a 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -107,10 +107,9 @@ cmLocalGenerator::cmLocalGenerator(cmGlobalGenerator* gg, cmMakefile* makefile)
   {
     std::vector<std::string> cpath;
     cmSystemTools::GetPath(cpath, "CPATH");
-    for (std::string& cp : cpath) {
+    for (std::string const& cp : cpath) {
       if (cmSystemTools::FileIsFullPath(cp)) {
-        cp = cmSystemTools::CollapseFullPath(cp);
-        this->EnvCPATH.emplace(std::move(cp));
+        this->EnvCPATH.emplace_back(cmSystemTools::CollapseFullPath(cp));
       }
     }
   }
@@ -1247,19 +1246,31 @@ std::vector<BT<std::string>> cmLocalGenerator::GetIncludeDirectoriesImplicit(
     }
   }
 
+  bool const isCorCxx = (lang == "C" || lang == "CXX");
+
+  // Resolve symlinks in CPATH for comparison with resolved include paths.
+  // We do this here instead of when EnvCPATH is populated in case symlinks
+  // on disk have changed in the meantime.
+  std::set<std::string> resolvedEnvCPATH;
+  if (isCorCxx) {
+    for (std::string const& i : this->EnvCPATH) {
+      resolvedEnvCPATH.emplace(this->GlobalGenerator->GetRealPath(i));
+    }
+  }
+
   // Checks if this is not an excluded (implicit) include directory.
-  auto notExcluded = [this, &implicitSet, &implicitExclude,
-                      &lang](std::string const& dir) {
-    return (
-      // Do not exclude directories that are not in an excluded set.
-      ((!cm::contains(implicitSet, this->GlobalGenerator->GetRealPath(dir))) &&
-       (!cm::contains(implicitExclude, dir)))
+  auto notExcluded = [this, &implicitSet, &implicitExclude, &resolvedEnvCPATH,
+                      isCorCxx](std::string const& dir) -> bool {
+    std::string const& real_dir = this->GlobalGenerator->GetRealPath(dir);
+    return
+      // Do not exclude directories that are not in any excluded set.
+      !(cm::contains(implicitSet, real_dir) ||
+        cm::contains(implicitExclude, dir))
       // Do not exclude entries of the CPATH environment variable even though
       // they are implicitly searched by the compiler.  They are meant to be
       // user-specified directories that can be re-ordered or converted to
       // -isystem without breaking real compiler builtin headers.
-      ||
-      ((lang == "C" || lang == "CXX") && cm::contains(this->EnvCPATH, dir)));
+      || (isCorCxx && cm::contains(resolvedEnvCPATH, real_dir));
   };
 
   // Get the target-specific include directories.