From c2750130ca4f7860b39ddfb4ff8355e27a7f72bf Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Sat, 22 Jun 2019 12:40:04 -0400
Subject: configure.ac: Check shell for 64-bit arithmetic

---
(limited to 'configure.ac')

diff --git a/configure.ac b/configure.ac
index c030ec2..113009a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -34,7 +34,7 @@ AM_CONDITIONAL([IN_GIT],
 AC_ARG_WITH(
 	[sh],
 	[AS_HELP_STRING([--with-sh=PATH],
-		[POSIX-conformant shell with `local'])],
+		[POSIX-conformant shell with `local' and 64-bit arithmetic])],
 	dnl This `dnl' is needed to workaround Vim syntax highlighting.
 	[
 		case "${withval}" in
@@ -57,6 +57,14 @@ AC_ARG_WITH(
 		fi
 	]
 )
+AC_MSG_CHECKING([whether ${SH} supports 64-bit arithmetic])
+if test x"$(${SH} -c 'printf "%s\n" "$((2 << 61))"' 2>&AS_MESSAGE_LOG_FD)" = \
+		x'4611686018427387904'; then
+	AC_MSG_RESULT([yes])
+else
+	AC_MSG_RESULT([no])
+	AC_MSG_ERROR([a shell with 64-bit arithmetic is required])
+fi
 
 AC_ARG_WITH(
 	[fakeroot],
--
cgit v0.9.1