Remove dllexport tags from static library builds.

code/CMakeLists.txt

@@ -1100,8 +1100,6 @@ if(MSVC10)
   endif()
 endif()
 
-ADD_DEFINITIONS( -DASSIMP_BUILD_DLL_EXPORT )
-
 IF( MSVC OR "${CMAKE_CXX_SIMULATE_ID}" MATCHES "MSVC") # clang with MSVC ABI
   ADD_DEFINITIONS( -D_SCL_SECURE_NO_WARNINGS )
   ADD_DEFINITIONS( -D_CRT_SECURE_NO_WARNINGS )
@@ -1178,6 +1176,13 @@ ENDIF()
 ADD_LIBRARY( assimp ${assimp_src} )
 ADD_LIBRARY(assimp::assimp ALIAS assimp)
 
+# Remove any dllexport tags when building a static library.
+IF (BUILD_SHARED_LIBS)
+  TARGET_COMPILE_DEFINITIONS(assimp PRIVATE ASSIMP_BUILD_DLL_EXPORT)
+ELSE ()
+  TARGET_COMPILE_DEFINITIONS(assimp PRIVATE OPENDDL_STATIC_LIBARY)
+ENDIF ()
+
 TARGET_USE_COMMON_OUTPUT_DIRECTORY(assimp)
 
 IF (ASSIMP_WARNINGS_AS_ERRORS)