diff --git a/CMakeLists.txt b/CMakeLists.txt
index d5bf92b..466e964 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -80,15 +80,13 @@ target_include_directories(epanet PUBLIC ${PROJECT_SOURCE_DIR}/include)
 
 
 # create export lib so we can link against dll using Visual Studio
-IF (GEN_X)
-	include(GenerateExportHeader)
-	GENERATE_EXPORT_HEADER(epanet
-    	BASE_NAME epanet
-   		EXPORT_MACRO_NAME DLLEXPORT
-    	EXPORT_FILE_NAME epanet_export.h
-    	STATIC_DEFINE SHARED_EXPORTS_BUILT_AS_STATIC)
-
+add_definitions(-D WITH_GENX)
+include(GenerateExportHeader)
+GENERATE_EXPORT_HEADER(epanet
+    BASE_NAME epanet
+    EXPORT_MACRO_NAME DLLEXPORT
+    EXPORT_FILE_NAME epanet_export.h
+    STATIC_DEFINE SHARED_EXPORTS_BUILT_AS_STATIC)
 
 file(COPY ${CMAKE_CURRENT_BINARY_DIR}/epanet_export.h
     DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/include)
-ENDIF (GEN_X)
diff --git a/appveyor.yml b/appveyor.yml
index 1c7c3ba..258b330 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -48,8 +48,7 @@ before_build:
   - mkdir %BUILD_HOME%
   - cd %BUILD_HOME%
   - cmake -G "%GENERATOR%" 
-    -DBUILD_TESTS=1 
-    -DGEN_X=1
+    -DBUILD_TESTS=1
     -DBOOST_ROOT="%BOOST_ROOT%"
     -DBoost_USE_STATIC_LIBS="ON" ..
 
diff --git a/include/epanet2.h b/include/epanet2.h
index 02b9033..042b83e 100644
--- a/include/epanet2.h
+++ b/include/epanet2.h
@@ -30,7 +30,7 @@
   #define EN_API_FLOAT_TYPE float
 #endif
 
-#ifdef GEN_X
+#ifdef WITH_GENX
   #include "epanet_export.h"
 #else 
   // --- define WINDOWS
diff --git a/run/CMakeLists.txt b/run/CMakeLists.txt
index 4822e95..53e792b 100644
--- a/run/CMakeLists.txt
+++ b/run/CMakeLists.txt
@@ -19,6 +19,7 @@ source_group("CLI" FILES ${EPANET_CLI_SOURCES})
 
 
 # Creates the EPANET command line executable
+add_definitions(-D WITH_GENX)
 add_executable(runepanet ${EPANET_CLI_SOURCES})
 if(NOT WIN32)
     target_link_libraries(runepanet LINK_PUBLIC epanet m)