2016-04-20: autotools: workaround for install-langDATA and install-siteDATA not

autotools: workaround for install-langDATA and install-siteDATA not honoring DESTDIR from distcheck

diff --git a/Makefile.am b/Makefile.am
--- a/Makefile.am
+++ b/Makefile.am
@@ -35,3 +35,18 @@ syntaxtestsreader.sh : ${WISP} wisp.scm 
 	chmod +x @abs_top_builddir@/$@
 
 TESTS=syntaxtests.sh syntaxtestsreader.sh
+
+# The installchecks won't work in a "make distcheck", because
+# they won't be installed in the final location used by the tools.
+# FIXME: automake should honor DESTDIR set by make distcheck
+if IS_MAKE_DISTCHECK
+install-siteDATA:
+	echo "Running 'make distcheck'; local installchecks disabled."
+install-langDATA:
+	echo "Running 'make distcheck'; local installchecks disabled."
+uninstall-siteDATA:
+	echo "Running 'make distcheck'; local installchecks disabled."
+uninstall-langDATA:
+	echo "Running 'make distcheck'; local installchecks disabled."
+else !IS_MAKE_DISTCHECK
+endif !IS_MAKE_DISTCHECK
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -20,6 +20,19 @@ AC_ARG_VAR([python3], [How to call Pytho
 AC_CHECK_TARGET_TOOL([python3], [python3], [no])
 AS_IF([test "x$python3" = "xno"],
       [AC_MSG_WARN([cannot find Python 3 which is required for development bootstrapping.])])
+
+# Is this a normal install, or a "make distcheck"?  We need to disable
+# the tests in a "make distcheck" that won't work.
+# FIXME: automake should honor DESTDIR set by make distcheck
+is_make_distcheck=no
+AS_CASE([$prefix],
+  [*/_inst],
+    [AC_MSG_NOTICE([[Prefix ends in /_inst; this is a 'make distcheck'.]])
+     is_make_distcheck=yes])
+AM_CONDITIONAL([IS_MAKE_DISTCHECK], [test "x$is_make_distcheck" = x"yes"])
+AC_MSG_CHECKING([final decision IS_MAKE_DISTCHECK (running "make distcheck"?)])
+AM_COND_IF([IS_MAKE_DISTCHECK], [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no])]) 
+
 # Run automake
 # Use GNU style. Note that ChangeLog is created on every commit 
 # by a commit hook in .hg/hgrc