patch 8.0.1379: configure check for selinux does not check for header file

Problem:    Configure check for selinux does not check for header file.
Solution:   Add an AC_CHECK_HEADER(). (Benny Siegert)
diff --git a/src/configure.ac b/src/configure.ac
index 938a77f..d08986e 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -433,8 +433,9 @@
   if test "$enable_selinux" = "yes"; then
     AC_MSG_RESULT(no)
     AC_CHECK_LIB(selinux, is_selinux_enabled,
+	[AC_CHECK_HEADER(selinux/selinux.h,
 	    [LIBS="$LIBS -lselinux"
-	     AC_DEFINE(HAVE_SELINUX)])
+	    AC_DEFINE(HAVE_SELINUX)])])
   else
      AC_MSG_RESULT(yes)
   fi