--- src/shaders/MaterialX/CMakeLists.txt.orig	2018-12-03 14:24:20 UTC
+++ src/shaders/MaterialX/CMakeLists.txt
@@ -64,7 +64,7 @@ macro (mx_oslc_compile)
         message (STATUS "oslc will make ${mxfile_justname} -> ${oslfile_justname} -> ${osofile_justname}")
     endif ()
     add_custom_command (OUTPUT ${osofile}
-        COMMAND python "${CMAKE_CURRENT_SOURCE_DIR}/build_materialX_osl.py"
+        COMMAND %%PYCMD%% "${CMAKE_CURRENT_SOURCE_DIR}/build_materialX_osl.py"
                        -s "${_shader_SHADERNAME}"
                        -m "${mxfile}"
                        -o "${oslfile}"
@@ -258,5 +258,5 @@ add_custom_target (mxshaders ALL
                    SOURCES ${shader_source} ${mx_shader_headers})
 
 install (FILES ${mx_shader_headers} ${mx_shader_objs} ${mx_shader_osls}
-         DESTINATION shaders/MaterialX)
+         DESTINATION %%DATADIR%%/shaders/MaterialX)