configure: Fix --with-linux when environment contains KSRC.

When "configure"'s environment contains KSRC, "configure" would use it in
preference to the value specified on --with-linux.  This caused a problem
for module-assistant builds in particular.

diff --git a/acinclude.m4 b/acinclude.m4
index 59c0c74..e89e0e9 100644 (file)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -57,6 +57,8 @@ AC_DEFUN([OVS_CHECK_LINUX], [
     elif test X"$with_l26_source" != X; then
       KSRC=$with_l26_source
       AC_MSG_WARN([--with-l26-source is deprecated, please use --with-linux-source instead])
+    else
+      KSRC=
     fi
   elif test X"$with_linux_source" != X || test X"$with_l26_source" != X; then
     AC_MSG_ERROR([Linux source directory may not be specified without Linux build directory])