The code below is C99 and supported by GCC in C++ mode since they allow C99 features.
Clang accepts the code in C99 mode, it (correctly) says that compound literals are a C99-specific feature in C++ mode, but with -std=gnu++0x (which should support GCC extensions, i.e. C99) I get the following error:
error: taking the address of a temporary object of type 'struct point' [-Waddress-of-temporary]
----------8<----------
struct point { int x; int y; };
void draw_point (struct point const* aPoint) { }
int main (int argc, char const* argv)
{
draw_point(&(struct point){ 1, 2 });
return 0;
}