set cmake include directories at target level
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3b70940..ab557ad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,12 +29,6 @@
   endif()
 endforeach()
 
-#
-# set up include dirs
-include_directories("${PROJECT_SOURCE_DIR}"
-  "${PROJECT_BINARY_DIR}"
-  )
-
 # Add src subdirectory
 add_subdirectory(double-conversion)
 
diff --git a/double-conversion/CMakeLists.txt b/double-conversion/CMakeLists.txt
index 0da50b1..fceedf9 100644
--- a/double-conversion/CMakeLists.txt
+++ b/double-conversion/CMakeLists.txt
@@ -23,6 +23,8 @@
 ${headers}
 )
 
+target_include_directories(double-conversion PUBLIC ..)
+
 #
 # associates the list of headers with the library
 # for the purposes of installation/import into other projects