acconfig.h

cygwin, 著名的在win32下模拟unix操作系统的东东

/* Define if DEBUGGING support is requested.  */
#undef DEBUGGING

/* Define if building "extra" thread-safe Cygwin DLL.  */
#undef _CYG_THREAD_FAILSAFE

/* Define if GCC supports builtin memset.  */
#undef HAVE_BUILTIN_MEMSET

/* Define if building thread-safe Cygwin DLL.  */
#undef _MT_SAFE

/* Define if using new vfork functionality. */
#undef NEWVFORK