For one, TESTS_SRC_DIR was missing even though it's present in
meson. For two, top_builddir/top_srcdir are relative paths, which
means the chdir added earlier would result in a wrong apps dir
being pointed to; fix that by making all paths passed into the
tests source absolute.
tests/elua/elua_suite.h
tests_elua_elua_suite_CPPFLAGS = -I$(top_builddir)/src/lib/efl \
--DTESTS_BUILD_DIR=\"$(top_builddir)/src/tests/elua\" \
+-DTESTS_BUILD_DIR=\"$(abs_top_builddir)/src/tests/elua\" \
+-DTESTS_SRC_DIR=\"$(abs_top_srcdir)/src/tests/elua\" \
-DPACKAGE_DATA_DIR=\"$(top_srcdir)/src/tests/elua\" \
-DPACKAGE_BUILD_DIR=\"$(abs_top_builddir)\" \
-DELUA_BINDINGS_DIR=\"$(ELUA_BINDINGS_DIR)\" \
-DELUA_CORE_DIR=\"$(ELUA_CORE_DIR)\" \
-DELUA_MODULES_DIR=\"$(ELUA_MODULES_DIR)\" \
--DELUA_APPS_DIR=\"$(top_srcdir)/src/tests/elua/data/apps\" \
+-DELUA_APPS_DIR=\"$(abs_top_srcdir)/src/tests/elua/data/apps\" \
@CHECK_CFLAGS@ \
@ELUA_CFLAGS@