Multi-Config generators should also set the debug suffix when enabled

Issue #2599

CMakeLists.txt

@@ -341,7 +341,7 @@ SET( ASSIMP_BIN_INSTALL_DIR "bin" CACHE STRING
 
 get_cmake_property(is_multi_config GENERATOR_IS_MULTI_CONFIG)
 
-IF (INJECT_DEBUG_POSTFIX AND (CMAKE_BUILD_TYPE STREQUAL "Debug"))
+IF (INJECT_DEBUG_POSTFIX AND (is_multi_config OR CMAKE_BUILD_TYPE STREQUAL "Debug"))
   SET(CMAKE_DEBUG_POSTFIX "d" CACHE STRING "Debug Postfix for lib, samples and tools")
 ELSE()
   SET(CMAKE_DEBUG_POSTFIX "" CACHE STRING "Debug Postfix for lib, samples and tools")