diff --git a/CMakeLists.txt b/CMakeLists.txt
index 397a3cc7..04632a9e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -335,6 +335,7 @@ target_include_directories(sta_swig
 
   PRIVATE
   ${STA_HOME}
+  ${TCL_INCLUDE_PATH}
 )
 
 ################################################################
@@ -436,12 +437,12 @@ add_library(OpenSTA
 target_include_directories(OpenSTA
   PUBLIC
   include
-  ${CUDD_INCLUDE}
   ${TCL_INCLUDE_PATH}
 
   PRIVATE
   include/sta
   ${STA_HOME}
+  ${CUDD_INCLUDE}
   )
 
 target_compile_features(OpenSTA
diff --git a/include/sta/Report.hh b/include/sta/Report.hh
index cfe7d64b..11fe305c 100644
--- a/include/sta/Report.hh
+++ b/include/sta/Report.hh
@@ -19,9 +19,10 @@
 #include <stdio.h>
 #include <stdarg.h>
 #include <string>
-#include <tcl.h>
 #include "DisallowCopyAssign.hh"
 
+struct Tcl_Interp;
+
 namespace sta {
 
 using std::string;