add AS_VAR_COPY for older autoconf versions

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/configure.ac b/configure.ac
index 1e2c713eecafcef15ddb6c75a822b1869cd1f04d..0909da30bd9be479b6bd6d63d3aa1b0cea706630 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -150,6 +150,16 @@ AM_COND_IF([ENABLE_PYTHON],
        PKG_CHECK_MODULES([PYTHONDEV], [python3 >= 3.2],[],[AC_MSG_ERROR([You must install python3-dev])])
        AC_DEFINE_UNQUOTED([ENABLE_PYTHON], 1, [Python3 is available])])
 
+# Not in older autoconf versions
+# AS_VAR_COPY(DEST, SOURCE)
+# -------------------------
+# Set the polymorphic shell variable DEST to the contents of the polymorphic
+# shell variable SOURCE.
+m4_ifdef([AS_VAR_COPY], [],
+[AC_DEFUN([AS_VAR_COPY],
+    [AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])])
+])
+
 dnl PKG_CHECK_VAR was introduced with pkg-config 0.28
 m4_ifdef([PKG_CHECK_VAR], [],
 [AC_DEFUN([PKG_CHECK_VAR],