Test pseudo-namespaces in C

In C you can create pseudo-namespaces by abusing structs of function
pointers, making function calls look like `module.func(x)` instead of
`func(x)`.

A lot of people online spout that this creates overhead, but this should
show that clang>=15.0.7 will still inline such function calls. GCC 11.3.1
is unable  to inline the function, but will still call the function
directly.

module.c

@@ -0,0 +1,12 @@
+
+#include "module.h"
+
+inline int succ(int x)
+{
+	return x+1;
+}
+
+struct exports module = {
+	.succ = succ,
+};
+