[aisleriot] build: Require bash to run configure

[Christian Persch <chpe src gnome org>]

commit 603a4f0a702b5ad38d10de9a1c8f81e4b8f5d441
Author: Christian Persch <chpe gnome org>
Date:   Mon Nov 3 18:43:17 2014 +0100

    build: Require bash to run configure
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726780

 configure.ac |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c810756..da24c4f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,6 +6,11 @@ AC_INIT([GNOME Patience], [3.15.0],
   [http://bugzilla.gnome.org/enter_bug.cgi?product=aisleriot],
   [aisleriot])
 
+# Must run under bash; see bug 726780
+if test -z "$BASH_VERSION"; then
+  AC_MSG_ERROR([Set CONFIG_SHELL to bash and try again.])
+fi
+
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/sol.c])
 AC_CONFIG_HEADERS([config.h])