fix lib64 directory issue

CMakeLists.txt

@@ -49,10 +49,8 @@ if (LINUX OR MINGW)
     message(FATAL_ERROR "Require at least gcc-8.0")
   endif()
 
-  link_directories( ${EXTERNAL_BUILD_ROOT}/lib64)
-
   set(ENV{PKG_CONFIG_PATH}
-    "${EXTERNAL_BUILD_ROOT}/lib64/pkgconfig:${EXTERNAL_BUILD_ROOT}/lib/pkgconfig:$ENV{PKG_CONFIG_PATH}"
+    "${EXTERNAL_BUILD_ROOT}/lib/pkgconfig:$ENV{PKG_CONFIG_PATH}"
   )
 
   find_package(PkgConfig REQUIRED)

cmake/settings.cmake

@@ -32,3 +32,8 @@ set(REPERTORY_OUTPUT_DIR ${CMAKE_BINARY_DIR})
 
 set(EXTERNAL_BUILD_ROOT ${CMAKE_BINARY_DIR}/external)
 set(EXTERNAL_BUILD_TYPE ${CMAKE_BUILD_TYPE})
+
+if (UNIX)
+  file(MAKE_DIRECTORY ${EXTERNAL_BUILD_ROOT}/lib64)
+  file(CREATE_LINK ${EXTERNAL_BUILD_ROOT}/lib64 ${EXTERNAL_BUILD_ROOT}/lib SYMBOLIC)
+endif()