test-sizeof: print pointer sizes

This is useful information, I don't know why we forgot to add it there.

gcc doesn't like arithemetic on a pointer to a function or void*, so don't
print signedness info there. It doesn't matter anyway.
C says function pointers can be different... Though I guess our code isn't
prepared for that.

src/test/test-sizeof.c

@@ -16,6 +16,11 @@
 
 DISABLE_WARNING_TYPE_LIMITS;
 
+#define info_no_sign(t)                                                 \
+        printf("%s → %zu bits, %zu byte alignment\n", STRINGIFY(t),     \
+               sizeof(t)*CHAR_BIT,                                      \
+               __alignof__(t))
+
 #define info(t)                                                         \
         printf("%s → %zu bits%s, %zu byte alignment\n", STRINGIFY(t),   \
                sizeof(t)*CHAR_BIT,                                      \
@@ -37,6 +42,12 @@ enum BigEnum2 {
 };
 
 int main(void) {
+        int (*function_pointer)(void);
+
+        info_no_sign(function_pointer);
+        info_no_sign(void*);
+        info(char*);
+
         info(char);
         info(signed char);
         info(unsigned char);