Matchers: Don't return twice when value to capture is missing

We called return_from_matcher once inside
matcher_evaluate_capturing_instruction and outside of it. That way we
returned not to the parent call stack entry but to the grandparent.

src/CMakeLists.txt

@@ -67,6 +67,7 @@ functionaltest("while")
 functionaltest("eq")
 functionaltest("chained-assignments")
 functionaltest("dictionary-assignments")
+functionaltest("variadic-functions")
 
 install(TARGETS apfl DESTINATION lib)
 install(TARGETS apfl-bin DESTINATION bin)

src/eval.c

@@ -1159,7 +1159,6 @@ matcher_evaluate_capturing_instruction(
     struct apfl_value cur;
 
     if (!matcher_current_val(ctx, cse, &cur)) {
-        return_from_matcher(ctx, false);
         return false;
     }
 

src/functional-tests/variadic-functions.at

@@ -0,0 +1,18 @@
+===== script =====
+foo = {
+x y z -> 3
+x y -> 2
+x -> 1
+-> 0
+}
+
+print (foo 1 1 1)
+print (foo 1 1)
+print (foo 1)
+print (foo)
+
+===== output =====
+3
+2
+1
+0