strings.h sys/socket.h sys/time.h unistd.h \
],,AC_MSG_ERROR([required C header missing!]))
# Optional header files
AC_CHECK_HEADERS_ONCE([ \
strings.h sys/socket.h sys/time.h unistd.h \
],,AC_MSG_ERROR([required C header missing!]))
# Optional header files
AC_CHECK_HEADERS_ONCE([ \
[ if test "$withval" != "no"; then
if test "$withval" != "yes"; then
CFLAGS="-I$withval/include $CFLAGS"
[ if test "$withval" != "no"; then
if test "$withval" != "yes"; then
CFLAGS="-I$withval/include $CFLAGS"