cmake HAVE_VFORK_H examples

HumbleNet/HumbleNet 3rdparty/libwebsockets/CMakeLists.txt :241 

CHECK_INCLUDE_FILE(vfork.h HAVE_VFORK_H)

InsightSoftwareConsortium/ITK Modules/ThirdParty/MINC/src/libminc/CMakeLists.txt :201 

CHECK_INCLUDE_FILES(vfork.h     HAVE_VFORK_H)

ShadowsocksR-Live/shadowsocksr-native cmake/configure.cmake :77 

check_include_files ( vfork.h HAVE_VFORK_H )

gccxml/gccxml GCC/config_cmake/CMakeLists.txt :201 

CHECK_INCLUDE_FILE(vfork.h HAVE_VFORK_H)