remove OpenBSD hardcode in check for sensor support

configure.ac

@@ -24,7 +24,6 @@ case $host_os in
 	*openbsd*)
 		AC_DEFINE([HAVE_ATTRIBUTE__BOUNDED__], [1], [OpenBSD has __bounded__])
 		AC_DEFINE([HAVE_ATTRIBUTE__DEAD], [1], [OpenBSD has __dead])
-		HAVE_SENSORS=true
 		;;
 	*solaris*)
 		HOST_OS=solaris
@@ -38,7 +37,6 @@ AM_CONDITIONAL([HOST_DARWIN],  [test x$HOST_OS = xdarwin])
 AM_CONDITIONAL([HOST_FREEBSD], [test x$HOST_OS = xfreebsd])
 AM_CONDITIONAL([HOST_LINUX],   [test x$HOST_OS = xlinux])
 AM_CONDITIONAL([HOST_SOLARIS], [test x$HOST_OS = xsolaris])
-AM_CONDITIONAL([HAVE_SENSORS], [test x$HAVE_SENSORS = xtrue ])
 
 AC_CHECK_FUNC([clock_gettime],,
 	[AC_SEARCH_LIBS([clock_gettime],[rt posix4])])
@@ -140,6 +138,10 @@ if test "x$ac_cv_have___va_copy" = "xyes" ; then
 fi
 
 AC_CHECK_HEADERS([sys/timex.h md5.h sha2.h])
+AC_CHECK_HEADERS([sys/sensors.h],
+	AM_CONDITIONAL(HAVE_SENSORS, true),
+	AM_CONDITIONAL(HAVE_SENSORS, false)
+)
 
 AC_CONFIG_FILES([
 	Makefile