Build failure on 10.6.8: `_runtime.h: error: expected ';', ',' or ')' before 'self'`

Not that I have high hopes here, but is it possible to fix this for 10.6 with some minimal changes?

```
building 'pyobjus' extension
creating build/temp.macosx-10.6-ppc-cpython-312/pyobjus
/opt/local/bin/gcc-mp-14 -Os -arch ppc -isysroot/ -I/opt/local/Library/Frameworks/Python.framework/Versions/3.12/include/python3.12 -c pyobjus/pyobjus.c -o build/temp.macosx-10.6-ppc-cpython-312/pyobjus/pyobjus.o
In file included from pyobjus/pyobjus.c:760:
pyobjus/_runtime.h: In function 'allocAndInitAutoreleasePool':
pyobjus/_runtime.h:34:11: warning: function called through a non-compatible type
   34 |   return ((id (*)(id, SEL)) objc_msgSend)(pool, sel_registerName("init"));
      |          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pyobjus/_runtime.h: In function 'drainAutoreleasePool':
pyobjus/_runtime.h:38:10: warning: function called through a non-compatible type
   38 |   (void)((id (*)(id, SEL)) objc_msgSend)(pool, sel_registerName("drain"));
      |         ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pyobjus/_runtime.h: In function 'objc_msgSend_custom':
pyobjus/_runtime.h:42:11: warning: function called through a non-compatible type
   42 |   return ((id (*)(id, SEL)) objc_msgSend)(obj, sel);
      |          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pyobjus/_runtime.h: At top level:
pyobjus/_runtime.h:52:46: error: expected ';', ',' or ')' before 'self'
   52 |   void objc_msgSend_stret__safe(id _Nullable self, SEL _Nonnull op){
      |                                              ^~~~
pyobjus/_runtime.h:58:57: error: expected ';', ',' or ')' before 'cif'
   58 |   ffi_status guarded_ffi_prep_cif_var(ffi_cif *_Nonnull cif, ffi_abi abi, unsigned int nfixedargs,
      |                                                         ^~~
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_6CArray_get_object_list':
pyobjus/pyobjus.c:11544:20: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
11544 |   __pyx_v_array = ((id *)__pyx_v_ptr);
      |                    ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_6CArray_get_class_list':
pyobjus/pyobjus.c:11658:20: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
11658 |   __pyx_v_array = ((Class *)__pyx_v_ptr);
      |                    ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_6CArray_get_sel_list':
pyobjus/pyobjus.c:11780:20: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
11780 |   __pyx_v_array = ((SEL *)__pyx_v_ptr);
      |                    ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_6CArray_as_struct_array':
pyobjus/pyobjus.c:14173:56: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
14173 |       (__pyx_v_cgrect_array[__pyx_v_i]) = (((CGRect *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_10)))[0]);
      |                                                        ^
pyobjus/pyobjus.c:14321:56: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
14321 |       (__pyx_v_cgsize_array[__pyx_v_i]) = (((CGSize *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_10)))[0]);
      |                                                        ^
pyobjus/pyobjus.c:14469:58: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
14469 |       (__pyx_v_cgpoint_array[__pyx_v_i]) = (((CGPoint *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_10)))[0]);
      |                                                          ^
pyobjus/pyobjus.c:14617:58: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
14617 |       (__pyx_v_cfrange_array[__pyx_v_i]) = (((CFRange *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_10)))[0]);
      |                                                          ^
pyobjus/pyobjus.c:14753:48: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
14753 |       (__pyx_v_id_array[__pyx_v_i]) = (((id *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_10)))[0]);
      |                                                ^
pyobjus/pyobjus.c: In function '__pyx_pf_7pyobjus_12ObjcProperty___cinit__':
pyobjus/pyobjus.c:21531:55: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
21531 |   (__pyx_v_self->property[0]) = (((objc_property_t *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_1)))[0]);
      |                                                       ^
pyobjus/pyobjus.c:21541:40: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
21541 |   (__pyx_v_self->ivar[0]) = (((Ivar *)((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_1)))[0]);
      |                                        ^
pyobjus/pyobjus.c: In function '__pyx_pf_7pyobjus_14dereference':
pyobjus/pyobjus.c:27280:23: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
27280 |     __pyx_v_c_addr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_4));
      |                       ^
pyobjus/pyobjus.c:27301:23: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
27301 |     __pyx_v_c_addr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_4));
      |                       ^
pyobjus/pyobjus.c:27373:59: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
27373 |       __pyx_t_5 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)__pyx_v_c_addr)); if (unlikely(!__pyx_t_5)) __PYX_ERR(4, 41, __pyx_L1_error)
      |                                                           ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_convert_cy_ret_to_py':
pyobjus/pyobjus.c:29631:45: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29631 |     __pyx_t_2 = __Pyx_PyInt_From_int(((int)((char)(__pyx_v_f_result[0])))); if (unlikely(!__pyx_t_2)) __PYX_ERR(4, 204, __pyx_L1_error)
      |                                             ^
pyobjus/pyobjus.c:29700:41: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29700 |     __pyx_t_4 = __Pyx_PyInt_From_short(((short)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 208, __pyx_L1_error)
      |                                         ^
pyobjus/pyobjus.c:29766:48: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29766 |     __pyx_t_4 = __Pyx_PyInt_From_PY_LONG_LONG(((PY_LONG_LONG)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 212, __pyx_L1_error)
      |                                                ^
pyobjus/pyobjus.c:29799:49: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29799 |     __pyx_t_4 = __Pyx_PyInt_From_unsigned_char(((unsigned char)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 214, __pyx_L1_error)
      |                                                 ^
pyobjus/pyobjus.c:29865:50: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29865 |     __pyx_t_4 = __Pyx_PyInt_From_unsigned_short(((unsigned short)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 218, __pyx_L1_error)
      |                                                  ^
pyobjus/pyobjus.c:29931:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29931 |     __pyx_t_4 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 222, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c:29969:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
29969 |     __pyx_t_2 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)__pyx_v_f_result)); if (unlikely(!__pyx_t_2)) __PYX_ERR(4, 224, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c:30092:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
30092 |     __pyx_t_3 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)__pyx_v_f_result)); if (unlikely(!__pyx_t_3)) __PYX_ERR(4, 226, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c:30555:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
30555 |     __pyx_t_4 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 258, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c:30577:59: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
30577 |       __pyx_t_4 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(__pyx_v_f_result[0]))); if (unlikely(!__pyx_t_4)) __PYX_ERR(4, 259, __pyx_L1_error)
      |                                                           ^
pyobjus/pyobjus.c:30722:62: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
30722 |         __pyx_t_10 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)__pyx_v_f_result)); if (unlikely(!__pyx_t_10)) __PYX_ERR(4, 262, __pyx_L1_error)
      |                                                              ^
pyobjus/pyobjus.c:31142:25: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
31142 |       __pyx_v_c_addr = ((unsigned PY_LONG_LONG)__pyx_v_f_result);
      |                         ^
pyobjus/pyobjus.c:31162:25: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
31162 |       __pyx_v_c_addr = ((unsigned PY_LONG_LONG)(__pyx_v_f_result[0]));
      |                         ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_convert_py_arg_to_cy':
pyobjus/pyobjus.c:34663:30: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
34663 |       __pyx_v_arg_val_ptr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                              ^
pyobjus/pyobjus.c:34739:30: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
34739 |       __pyx_v_arg_val_ptr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                              ^
pyobjus/pyobjus.c:37408:31: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
37408 |       __pyx_v_str_long_ptr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                               ^
pyobjus/pyobjus.c:37419:59: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
37419 |       __pyx_t_8 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)__pyx_v_str_long_ptr)); if (unlikely(!__pyx_t_8)) __PYX_ERR(4, 665, __pyx_L1_error)
      |                                                           ^
pyobjus/pyobjus.c:37490:33: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
37490 |         __pyx_v_str_long_ptr = ((unsigned PY_LONG_LONG *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                                 ^
pyobjus/pyobjus.c:37615:42: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
37615 |       (((void **)__pyx_v_val_ptr)[0]) = ((void *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                                          ^
pyobjus/pyobjus.c:37803:44: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
37803 |         (((void **)__pyx_v_val_ptr)[0]) = ((void *)((unsigned PY_LONG_LONG)__pyx_t_11));
      |                                            ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_10ObjcMethod_ensure_method':
pyobjus/pyobjus.c:41820:22: error: implicit declaration of function 'guarded_ffi_prep_cif_var' [-Wimplicit-function-declaration]
41820 |   __pyx_v_f_status = guarded_ffi_prep_cif_var((&__pyx_v_self->f_cif), FFI_DEFAULT_ABI, __pyx_v_num_fixed_args, __pyx_v_num_args, __pyx_v_self->f_result_type, __pyx_v_self->f_arg_types);
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~
pyobjus/pyobjus.c: In function '__pyx_pf_7pyobjus_10ObjcMethod_10__call__':
pyobjus/pyobjus.c:43891:75: error: 'objc_msgSend_stret__safe' undeclared (first use in this function); did you mean 'objc_msgSend_stret'?
43891 |       ffi_call((&__pyx_v_self->f_cif), ((void (*)(void))((id (*)(id, SEL))objc_msgSend_stret__safe)), __pyx_v_res_ptr, __pyx_v_f_args);
      |                                                                           ^~~~~~~~~~~~~~~~~~~~~~~~
      |                                                                           objc_msgSend_stret
pyobjus/pyobjus.c:43891:75: note: each undeclared identifier is reported only once for each function it appears in
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_get_class_properties':
pyobjus/pyobjus.c:45764:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
45764 |     __pyx_t_1 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(&(__pyx_v_properties[__pyx_v_i])))); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 655, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c:45768:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
45768 |     __pyx_t_6 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(&__pyx_v_ivar))); if (unlikely(!__pyx_t_6)) __PYX_ERR(0, 655, __pyx_L1_error)
      |                                                         ^
pyobjus/pyobjus.c: In function '__pyx_f_7pyobjus_protocol_forwardInvocation':
pyobjus/pyobjus.c:48725:57: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
48725 |     __pyx_t_3 = __Pyx_PyInt_From_unsigned_PY_LONG_LONG(((unsigned PY_LONG_LONG)(&__pyx_v_c_arg))); if (unlikely(!__pyx_t_3)) __PYX_ERR(0, 858, __pyx_L1_error)
      |                                                         ^
error: command '/opt/local/bin/gcc-mp-14' failed with exit code 1
Command failed:  cd "/opt/local/var/macports/build/py312-pyobjus-a0c31f18/work/pyobjus-1.2.3" && /opt/local/Library/Frameworks/Python.framework/Versions/3.12/bin/python3.12 setup.py --no-user-cfg build -j6
Exit code: 1
```

Start by reproducing the macOS 10.6 PPC build command shown in the report, then inspect the declarations around lines 52 and 58 of pyobjus/_runtime.h and the guarded_ffi_prep_cif_var call in pyobjus/pyobjus.c. Done means the extension builds successfully on the reported Python 3.12 and 10.6 PPC environment without these compilation errors.

Written by the indexing model from the issue text.