test: Use SH_LOG_COMPILER and AM_TESTS_ENVIRONMENT

TESTS_ENVIRONMENT is deprecated and should be reserved to the user to
override the test environment

<ext>_LOG_COMPILER is meant to contain the program that runs the test
with <ext> extension
AM_TESTS_ENVIRONMENT is meant to set the environment for the tests

  https://bugs.freedesktop.org/show_bug.cgi?id=60192

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>

test/Makefile.am

@@ -1,5 +1,15 @@
 check_SCRIPTS=run-test.sh
-TESTS_ENVIRONMENT=src=${srcdir} EXEEXT=${EXEEXT} sh
+TEST_EXTENSIONS = \
+	.sh
+
+AM_TESTS_ENVIRONMENT= \
+	src=${srcdir}; \
+	EXEEXT=${EXEEXT}; \
+	export src; \
+	export EXEEXT;
+
+SH_LOG_COMPILER = sh
+
 TESTS=run-test.sh
 
 TESTDATA=4x6.pcf 8x16.pcf out.expected fonts.conf.in