diff --git a/project/config/cfgdefs.in b/project/config/cfgdefs.in
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/project/config/cfgdefs.in
diff --git a/project/config/cfgdefs.sh b/project/config/cfgdefs.sh
index 8400b6a..22b94c3 100644
--- a/project/config/cfgdefs.sh
+++ b/project/config/cfgdefs.sh
@@ -10,6 +10,11 @@
 # finally, cfgdefs.sh may update the contents of the
 # config-time generated cfgdefs.mk.
 
+
+# sofort's config test framework
+. "$mb_project_dir/sofort/cfgtest/cfgtest.sh"
+
+
 for arg ; do
 	case "$arg" in
 		*)
@@ -81,8 +86,100 @@ cfgdefs_bootstrap()
 	cfgdefs_bootstrap_done='yes'
 }
 
+
+cfgdefs_output_custom_defs()
+{
+	cat "$mb_project_dir/project/config/cfgdefs.in" > cfgdefs.mk
+}
+
+
+cfgdefs_perform_utility_tests()
+{
+	# utility settings
+	cfgtest_comment 'utility settings'
+
+	mb_cfgtest_makevar='SYS_MK_DIR'
+	cfgtest_makevar_append '$(DATADIR)/mk'
+	cfgtest_cflags_append '-D_PATH_DEFSYSPATH=\"$(SYS_MK_DIR)\"'
+
+	cfgtest_newline
+}
+
+
+cfgdefs_perform_common_tests()
+{
+	# interfaces
+	mb_cfgtest_headers='stdio.h'
+	cfgtest_interface_presence 'vsnprintf'
+
+	mb_cfgtest_headers='string.h'
+	cfgtest_interface_presence 'strerror'
+
+	mb_cfgtest_headers='sys/types.h unistd.h'
+	cfgtest_interface_presence 'setpgid'
+
+	mb_cfgtest_headers='sys/time.h sys/resource.h'
+	cfgtest_interface_presence 'setrlimit'
+
+	mb_cfgtest_headers='stdlib.h'
+	cfgtest_interface_presence 'setenv'
+
+	cfgtest_newline
+}
+
+
+cfgdefs_perform_native_tests()
+{
+	# init
+	cfgtest_newline
+	cfgtest_native_section
+
+	# common tests
+	cfgdefs_perform_common_tests
+
+	# pretty cfgdefs.mk
+	cfgtest_newline
+}
+
+cfgdefs_perform_target_tests()
+{
+	# init
+	cfgtest_newline
+	cfgtest_host_section
+
+	# common tests
+	cfgdefs_perform_common_tests
+
+	# utility tests
+	cfgdefs_perform_utility_tests
+
+	# pretty cfgdefs.mk
+	cfgtest_newline
+}
+
+# cfgdefs.in --> cfgdefs.mk
+cfgdefs_output_custom_defs
+
+# strict: some tests might fail
+set +e
+
+# bootstrapping cflags
+cfgdefs_perform_native_tests
+
+# strict: restore mode
+set -e
+
 # bootstrap
 cfgdefs_bootstrap
 
+# strict: some tests might fail
+set +e
+
+# target-specific tests
+cfgdefs_perform_target_tests
+
+# strict: restore mode
+set -e
+
 # all done
 return 0