Allow passing user signals to (signal) as keywords.

examples/ffi/so.c

@@ -124,7 +124,8 @@ void void_fn(void) {
     printf("void fn ran\n");
 }
 
-EXPORTER void_fn_2(double y) {
+EXPORTER
+void void_fn_2(double y) {
     printf("y = %f\n", y);
 }
 
@@ -132,3 +133,13 @@ EXPORTER
 void void_ret_fn(int x) {
     printf("void fn ran: %d\n", x);
 }
+
+typedef struct {
+    int a, b;
+    float c, d;
+} Split;
+
+EXPORTER
+float split_fn(Split s) {
+    return s.a * s.c + s.b * s.d;
+}

examples/ffi/test.janet

@@ -45,6 +45,8 @@
    j :double])
 (ffi/defbind void-fn-2 :void [y :double])
 
+(def split (ffi/struct :int :int :float :float))
+(ffi/defbind split-fn :float [s split])
 #
 # Struct reading and writing
 #
@@ -85,6 +87,7 @@
 # Call functions
 #
 
+(tracev (split-fn [5 6 1.2 3.4]))
 (tracev (void-fn-2 10.3))
 (tracev (double-many 1 2 3 4 5 6))
 (tracev (string/format "%.17g" (double-many 1 2 3 4 5 6)))