Simplify MKLML download command

cmake/external/mklml.cmake

@@ -43,8 +43,8 @@ SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_RPATH}" "${MKLML_ROOT}/lib")
 
 INCLUDE_DIRECTORIES(${MKLML_INC_DIR})
 
-SET(mklml_cmakefile ${MKLML_DOWNLOAD_DIR}/CMakeLists.txt)
-FILE(WRITE ${mklml_cmakefile} "PROJECT(MKLML)\n"
+FILE(WRITE ${MKLML_DOWNLOAD_DIR}/CMakeLists.txt
+  "PROJECT(MKLML)\n"
   "cmake_minimum_required(VERSION 3.0)\n"
   "install(DIRECTORY ${MKLML_VER}\n"
   "        DESTINATION ${MKLML_DST_DIR})\n")
@@ -54,8 +54,7 @@ ExternalProject_Add(
     ${EXTERNAL_PROJECT_LOG_ARGS}
     PREFIX                ${MKLML_SOURCE_DIR}
     DOWNLOAD_DIR          ${MKLML_DOWNLOAD_DIR}
-    DOWNLOAD_COMMAND      wget --quiet --no-check-certificate -O ${MKLML_DOWNLOAD_DIR}/${MKLML_VER}.tgz ${MKLML_URL}
-                          && tar -xzf ${MKLML_DOWNLOAD_DIR}/${MKLML_VER}.tgz
+    DOWNLOAD_COMMAND      wget --no-check-certificate -qO- ${MKLML_URL} | tar xz -C ${MKLML_DOWNLOAD_DIR}
     DOWNLOAD_NO_PROGRESS  1
     UPDATE_COMMAND        ""
     CMAKE_ARGS            -DCMAKE_INSTALL_PREFIX=${MKLML_INSTALL_ROOT}