cgo: implement Go arrays (constant arrays in C)

testdata/cgo/main.c

@@ -9,6 +9,7 @@ _Complex float globalComplexFloat = 4.1+3.3i;
 _Complex double globalComplexDouble = 4.2+3.4i;
 _Complex double globalComplexLongDouble = 4.3+3.5i;
 collection_t globalStruct = {256, -123456, 3.14};
+short globalArray[3] = {5, 6, 7};
 
 int fortytwo() {
 	return 42;

testdata/cgo/main.go

@@ -37,6 +37,8 @@ func main() {
 	println("complex double:", C.globalComplexDouble)
 	println("complex long double:", C.globalComplexLongDouble)
 	println("struct:", C.globalStruct.s, C.globalStruct.l, C.globalStruct.f)
+	var _ [3]C.short = C.globalArray
+	println("array:", C.globalArray[0], C.globalArray[1], C.globalArray[2])
 }
 
 //export mul

testdata/cgo/main.h

@@ -21,6 +21,7 @@ extern _Complex float globalComplexFloat;
 extern _Complex double globalComplexDouble;
 extern _Complex double globalComplexLongDouble;
 extern collection_t globalStruct;
+extern short globalArray[3];
 
 // test duplicate definitions
 int add(int a, int b);