[4.0] 62c20c7 define AS_COPY_VAR in varnish.m4 if not already defined (autoconf < 2.63b) found at: http://www.open-mpi.org/community/lists/devel/2010/09/8472.php

[Lasse Karstensen]

commit 62c20c7c90afe2f3db5a611255b575e0e784b7c8
Author: Geoff Simmons <geoff at uplex.de>
Date:   Mon Dec 15 14:34:18 2014 +0100

    define AS_COPY_VAR in varnish.m4 if not already defined (autoconf < 2.63b)
    found at: http://www.open-mpi.org/community/lists/devel/2010/09/8472.php

diff --git a/varnish.m4 b/varnish.m4
index 16e27c5..d603e2b 100644
--- a/varnish.m4
+++ b/varnish.m4
@@ -28,6 +28,11 @@
 # SUCH DAMAGE.
 #
 
+# For compatibility with autoconf < 2.63b
+m4_ifndef([AS_VAR_COPY],
+  [m4_define([AS_VAR_COPY],
+     [AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])])]) 
+
 # VARNISH_VMOD_INCLUDE_DIR([])
 # ----------------------------