cmake HAVE_VFPRINTF examples

SCIInstitute/SCIRun src/Externals/libxml2/CMakeLists.txt :162 

CHECK_FUNCTION_EXISTS("vfprintf" HAVE_VFPRINTF)

gccxml/gccxml GCC/config_cmake/CMakeLists.txt :245 

CHECK_FUNCTION_EXISTS(vfprintf HAVE_VFPRINTF)