diff --git a/CMakeLists.txt b/CMakeLists.txt
index fb5ba476..1d79d8eb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -194,8 +194,10 @@ install(
 ########################################
 add_custom_command(TARGET mist
   POST_BUILD
-  COMMAND mkdir -p ${BINARY_DIR}/mist
-  COMMAND cp ${libHeaders} ${BINARY_DIR}/mist
+  COMMAND ${CMAKE_COMMAND}
+  ARGS    -E make_directory ${BINARY_DIR}/mist
+  COMMAND ${CMAKE_COMMAND}
+  ARGS    -E copy_if_different ${libHeaders} ${BINARY_DIR}/mist
   DEPENDS ${libHeaders}
 )
 
@@ -358,10 +360,10 @@ endif(DOXYGEN_FOUND)
 if (CMAKE_CROSSCOMPILING)
   set(RUNA "1")
 else()
-  try_run(RUNA RUNB ${BINARY_DIR}/CMakeTmp ${SOURCE_DIR}/src/sourcery.cpp)
+  try_run(RUNA RUNB ${BINARY_DIR}/CMakeTmp ${SOURCE_DIR}/src/sourcery.cpp )
 endif()
 
-if("${RUNA}" EQUAL "0")
+if("${RUNA}" EQUAL "2")
   message("Not cross compiling - building sourcery")
   add_executable(sourcery
     src/sourcery.cpp
diff --git a/src/sourcery.cpp b/src/sourcery.cpp
index cf157d1e..1e54343d 100644
--- a/src/sourcery.cpp
+++ b/src/sourcery.cpp
@@ -8,7 +8,7 @@
 int main(int argc, char* argv[]){
   if (argc < 4) {
     std::cerr << "Usage: " << argv[0] << " <inputFile> <variableName> <outputFile>" << std::endl;
-    return 1;
+    return 2;
   }
   std::ofstream tmp(argv[3]);
   //begin the first line