Force usage of Vulkan headers from submodule

Signed-off-by: Tobias Frisch <tfrisch@uni-koblenz.de>

config/lib/Vulkan.cmake

@@ -2,27 +2,19 @@
 find_package(Vulkan REQUIRED)
 
 if (Vulkan_FOUND)
-    if (NOT EXISTS ${Vulkan_INCLUDE_DIR}/vulkan/vulkan.h)
-        use_git_submodule("${vkcv_lib_path}/Vulkan-Headers" vulkan_headers_status)
-        
-        if (${vulkan_headers_status})
-            list(APPEND vkcv_includes ${vkcv_lib}/Vulkan-Headers/include)
-        endif()
-    else()
-        list(APPEND vkcv_includes ${Vulkan_INCLUDE_DIR})
+    use_git_submodule("${vkcv_lib_path}/Vulkan-Headers" vulkan_headers_status)
+    
+    if (${vulkan_headers_status})
+        list(APPEND vkcv_includes ${vkcv_lib_path}/Vulkan-Headers/include)
     endif()
 
-    if (NOT EXISTS ${Vulkan_INCLUDE_DIR}/vulkan/vulkan.hpp)
-        use_git_submodule("${vkcv_lib_path}/Vulkan-Hpp" vulkan_hpp_status)
-    
-        if (${vulkan_hpp_status})
-            list(APPEND vkcv_includes ${vkcv_lib}/Vulkan-Hpp)
-        endif()
-    else()
-        list(APPEND vkcv_includes ${Vulkan_INCLUDE_DIR})
+    use_git_submodule("${vkcv_lib_path}/Vulkan-Hpp" vulkan_hpp_status)
+
+    if (${vulkan_hpp_status})
+        list(APPEND vkcv_includes ${vkcv_lib_path}/Vulkan-Hpp)
     endif()
     
     list(APPEND vkcv_libraries ${Vulkan_LIBRARIES})
 
-    message(${vkcv_config_msg} " Vulkan  -   ")
+    message(${vkcv_config_msg} " Vulkan  -   " ${Vulkan_VERSION})
 endif ()