(testsuite) Add basic tests for make.

test/completion/make.exp

@@ -0,0 +1,3 @@
+if {[assert_bash_type make]} {
+    source "lib/completions/make.exp"
+}; # if

test/lib/completions/make.exp

@@ -0,0 +1,20 @@
+proc setup {} {
+    save_env
+}; # setup()
+
+
+proc teardown {} {
+    assert_env_unmodified
+}; # teardown()
+
+
+setup
+
+
+assert_complete_any "make "
+
+
+sync_after_int
+
+
+teardown