testsuite: Add trivial tests for Go closures

testsuite/libffi.go/closure1.c

@@ -0,0 +1,28 @@
+/* { dg-do run } */
+
+#include "ffitest.h"
+
+void doit(ffi_cif *cif, void *rvalue, void **avalue, void *closure)
+{
+  (void)cif;
+  (void)avalue;
+  *(void **)rvalue = closure;
+}
+
+typedef void * (*FN)(void);
+
+int main()
+{
+  ffi_cif cif;
+  ffi_go_closure cl;
+  void *result;
+
+  CHECK(ffi_prep_cif(&cif, ABI_NUM, 0, &ffi_type_pointer, NULL) == FFI_OK);
+  CHECK(ffi_prep_go_closure(&cl, &cif, doit) == FFI_OK);
+
+  ffi_call_go(&cif, FFI_FN(*(FN *)&cl), &result, NULL, &cl);
+
+  CHECK(result == &cl);
+
+  exit(0);
+}