fix

Author: facontidavide

CMakeLists.txt

@@ -199,7 +199,7 @@ if (WIN32)
     list(APPEND BT_SOURCE src/shared_library_WIN.cpp )
 endif()
 
-if (BUILD_SHARED_LIBS)
+if (BTCPP_SHARED_LIBS)
     set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
     add_library(${BEHAVIOR_TREE_LIBRARY} SHARED ${BT_SOURCE})
 else()