Search for the correct include and lib directories for the DX SDK

And only set them when needed.

CMakeLists.txt

@@ -230,9 +230,6 @@ IF(MSVC)
     ENDIF()
     IF(DXSDK_DIR)
         MESSAGE(STATUS "Using DirectX SDK directory: ${DXSDK_DIR}")
-        SET(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES} "${DXSDK_DIR}/Include")
-        INCLUDE_DIRECTORIES("${DXSDK_DIR}/Include")
-        LINK_DIRECTORIES("${DXSDK_DIR}/Lib")
     ENDIF()
 
     OPTION(FORCE_STATIC_VCRT "Force /MT for static VC runtimes" OFF)

cmake/FindDSound.cmake

@@ -9,14 +9,16 @@
 #
 
 find_path(DSOUND_INCLUDE_DIR
-          PATHS "${DXSDK_DIR}/include"
           NAMES dsound.h
+          PATHS "${DXSDK_DIR}"
+          PATH_SUFFIXES include
           DOC "The DirectSound include directory"
 )
 
 find_library(DSOUND_LIBRARY
-             PATHS "${DXSDK_DIR}/lib"
              NAMES dsound
+             PATHS "${DXSDK_DIR}"
+             PATH_SUFFIXES lib lib/x86 lib/x64
              DOC "The DirectSound library"
 )