Drop required automake version back to 1.11.3

Work around broken automake-1.13 changes.

configure.ac

@@ -9,7 +9,8 @@ AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/harfbuzz.pc.in])
 AC_CONFIG_HEADERS([config.h])
 
-AM_INIT_AUTOMAKE([1.13 gnits tar-pax dist-bzip2 no-dist-gzip -Wall no-define color-tests -Wno-portability])
+AM_INIT_AUTOMAKE([1.11.1 gnits tar-pax dist-bzip2 no-dist-gzip -Wall no-define color-tests -Wno-portability])
+AM_CONDITIONAL(AUTOMAKE_OLDER_THAN_1_13, test $am__api_version = 1.11 -o $am__api_version = 1.12)
 AM_SILENT_RULES([yes])
 
 # Initialize libtool

test/shaping/Makefile.am

@@ -49,6 +49,13 @@ AM_TESTS_ENVIRONMENT = \
 	export builddir; \
 	$(NULL)
 
+if AUTOMAKE_OLDER_THAN_1_13
+TESTS_ENVIRONMENT = \
+	$(AM_TESTS_ENVIRONMENT) \
+	$(TESTS_LOG_COMPILER) \
+	$(NULL)
+endif
+
 TESTS_LOG_COMPILER = sh $(srcdir)/run-tests.sh
 
 .PHONY: manifests