执行完CMake之后再执行make时遇到以下错误
[ %] Generating precomp.hpp.gch/opencv_core_Release.gch
In file included from /usr/include/c++//bits/stl_algo.h::,
from /usr/include/c++//algorithm:,
from /opt/opencv/opencv-3.1./modules/core/include/opencv2/core/base.hpp:,
from /opt/opencv/opencv-3.1./modules/core/include/opencv2/core.hpp:,
from /opt/opencv/opencv-3.1./modules/core/include/opencv2/core/utility.hpp:,
from /opt/opencv/build/modules/core/precomp.hpp::
/usr/include/c++//cstdlib::: fatal error: stdlib.h: 没有那个文件或目录
#include_next <stdlib.h>
^
compilation terminated.
modules/core/CMakeFiles/pch_Generate_opencv_core.dir/build.make:: recipe for target 'modules/core/precomp.hpp.gch/opencv_core_Release.gch' failed
make[]: *** [modules/core/precomp.hpp.gch/opencv_core_Release.gch] Error
CMakeFiles/Makefile2:: recipe for target 'modules/core/CMakeFiles/pch_Generate_opencv_core.dir/all' failed
make[]: *** [modules/core/CMakeFiles/pch_Generate_opencv_core.dir/all] Error
Makefile:: recipe for target 'all' failed
make: *** [all] Error
这是由于gcc6已经吧stdlib.h纳入了libstdc++以进行更好的优化，C Library的头文件stdlib.h使用 Include_next，而include_next对gcc系统头文件路径很敏感。
推荐的修复方法是不要把include路径作为系统目录，而是使用标准方式包含include 目录
翻译自 https://bugs.webkit.org/show_bug.cgi?id=161697
原文说明：
Trying to build WebKitGTK+ with GCC I got this error: In file included from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/sysroots/qemux86/usr/include/c++/6.2./ext/string_conversions.h::,
from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/sysroots/qemux86/usr/include/c++/6.2./bits/basic_string.h:,
from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/sysroots/qemux86/usr/include/c++/6.2./string:,
from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/work/i586-oe-linux/webkitgtk/2.12.-r0/webkitgtk-2.12./Source/ThirdParty/ANGLE/src/common/debug.h:,
from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/work/i586-oe-linux/webkitgtk/2.12.-r0/webkitgtk-2.12./Source/ThirdParty/ANGLE/src/common/mathutil.h:,
from /home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/work/i586-oe-linux/webkitgtk/2.12.-r0/webkitgtk-2.12./Source/ThirdParty/ANGLE/src/common/mathutil.cpp::
/home/igalia/clopez/yocto/commit-builds/meta-webkit/builds/qemux86-/tmp-glibc/sysroots/qemux86/usr/include/c++/6.2./cstdlib::: fatal error: stdlib.h: No such file or directory
#include_next <stdlib.h> The issue seems to be that GCC has now introduced stdlib.h in libstdc++ for better compliance and its including the C library stdlib.h using include_next which is sensitive to order of system header include paths. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129 The recommended way to fix this is to stop adding include directories as system ones (-isystem) and instead use the standard way to include directories (-I) The openembedded project is carrying this downstream patch against WebKitGTK+ 2.12 with the above fix: http://git.openembedded.org/openembedded-core/tree/meta/recipes-sato/webkit/files/0001-WebKitMacros-Append-to-I-and-not-to-isystem.patch
OpenCV对gcc6支持不完善，导致gcc不兼容OpenCV
解决方法：卸载Ubuntu 16，使用Ubuntu 14
===========================================================
以上解法其实没有必要，gcc6并不是不能编译OpenCV 3，加入以下编译选项即可
-DENABLE_PRECOMPILED_HEADERS=OFF
知识来源：https://www.cnblogs.com/wuchaodzxx/p/8418980.html
感谢提供解法。