autoconf: fix --with(out)-sendfile-support option handling

this fixes bug #8344

diff --git a/source3/configure.in b/source3/configure.in
index e6a13102d50a01649b0f7bdf20ee85a27490e6d6..a6cc4440f1e356ee382423f845ca5cddb6a35f8c 100644 (file)
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -5443,16 +5443,23 @@ fi
 #################################################
 # check for sendfile support
 
-with_sendfile_support=yes
-AC_MSG_CHECKING(whether to check to support sendfile)
+AC_MSG_CHECKING(whether sendfile support should be built in)
 AC_ARG_WITH(sendfile-support,
-[AS_HELP_STRING([--with-sendfile-support], [Check for sendfile support (default=yes)])],
+[AS_HELP_STRING([--with-sendfile-support], [Whether sendfile support should be built in (default=auto)])],
 [ case "$withval" in
-  yes)
-
-       AC_MSG_RESULT(yes);
+  yes|no)
+       AC_MSG_RESULT($withval);
+       with_sendfile_support=$withval
+       ;;
+  *)
+       AC_MSG_RESULT(yes)
+       with_sendfile_support=auto
+       ;;
+  esac ],
+)
 
-       case "$host_os" in
+if test x$with_sendfile_support != xno ; then
+    case "$host_os" in
        *linux* | gnu* | k*bsd*-gnu | kopensolaris*-gnu)
                AC_CACHE_CHECK([for linux sendfile support],samba_cv_HAVE_SENDFILE,[
                AC_TRY_LINK([#include <sys/sendfile.h>],
@@ -5629,14 +5636,12 @@ samba_cv_HAVE_SENDFILE=yes,samba_cv_HAVE_SENDFILE=no)])
        ;;
        *)
        ;;
-        esac
-        ;;
-  *)
-    AC_MSG_RESULT(no)
-    ;;
-  esac ],
-  AC_MSG_RESULT(yes)
-)
+    esac
+fi
+
+if test x$with_sendfile_support = xyes -a x"$samba_cv_HAVE_SENDFILE" != xyes ; then
+       AC_MSG_ERROR(sendfile support requested but sendfile not available )
+fi
 
 ############################################
 # See if we have the Linux readahead syscall.