编译opencv3.0出现以下问题：

Make Error at 3rdparty/ippicv/downloader.cmake:75 (message):
  ICV: Failed to download ICV package: ippicv_linux_20140513.tgz.
  Status=28;"Timeout was reached"
Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:212 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:449 (include)

在该网站：https://sourceforge.net/projects/opencvlibrary/files/3rdparty/ippicv/

下载

ippicv_linux_20140513

替换opencv-3.0.0/3rdparty/ippicv/downloads/linux-8b449a536a2157bcad08a2b9f266828b下面的压缩包即可