--- a/External/CMakeLists.txt
+++ b/External/CMakeLists.txt
@@ -71,7 +71,8 @@ endif()
 if(ENABLE_OPT AND NOT TARGET SPIRV-Tools-opt)
     if(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/spirv-tools)
         set(SPIRV_SKIP_TESTS ON CACHE BOOL "Skip building SPIRV-Tools tests")
-        add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/spirv-tools spirv-tools)
+        set(BUILD_SHARED_LIBS OFF CACHE BOOL "Disable build shared libs" FORCE)
+        add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/spirv-tools EXCLUDE_FROM_ALL)
     endif()
 endif()
 
--- a/SPIRV/CMakeLists.txt
+++ b/SPIRV/CMakeLists.txt
@@ -100,7 +100,7 @@ if(ENABLE_OPT)
     target_link_libraries(SPIRV PRIVATE MachineIndependent SPIRV-Tools-opt)
     target_include_directories(SPIRV PUBLIC
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../External>
-        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/External>)
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 else()
     target_link_libraries(SPIRV PRIVATE MachineIndependent)
 endif()
--- a/StandAlone/CMakeLists.txt
+++ b/StandAlone/CMakeLists.txt
@@ -83,7 +83,7 @@ endif()
 target_link_libraries(glslangValidator ${LIBRARIES})
 target_include_directories(glslangValidator PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../External>
-    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/External>)
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 
 if(ENABLE_OPT)
     target_include_directories(glslangValidator