qsort_r break builds on macOS

I'm using apk on macOS to generate packages. It's broken since commit 1d473e00.

Warning during compilation:

❯ ninja -C build 
ninja: Entering directory `build'
[1/6] Compiling C object src/libapk.2.dylib.p/adb.c.o
../src/adb.c:991:79: warning: incompatible pointer types passing 'struct wacmp_param *' to parameter of type 'int (* _Nonnull)(void *, const void *, const void *)' [-Wincompatible-pointer-types]
                qsort_r(&arr->obj[ADBI_FIRST], adb_ra_num(arr), sizeof(arr->obj[0]), wacmp, &arg);
                                                                                            ^~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdlib.h:342:22: note: passing argument to parameter '__compar' here
            int (* _Nonnull __compar)(void *, const void *, const void *));
                            ^
../src/adb.c:995:81: warning: incompatible pointer types passing 'struct wacmp_param *' to parameter of type 'int (* _Nonnull)(void *, const void *, const void *)' [-Wincompatible-pointer-types]
                qsort_r(&arr->obj[ADBI_FIRST], adb_ra_num(arr), sizeof(arr->obj[0]), wadbcmp, &arg);
                                                                                              ^~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdlib.h:342:22: note: passing argument to parameter '__compar' here
            int (* _Nonnull __compar)(void *, const void *, const void *));
                            ^
2 warnings generated.
[2/6] Compiling C object src/libapk.a.p/adb.c.o
../src/adb.c:991:79: warning: incompatible pointer types passing 'struct wacmp_param *' to parameter of type 'int (* _Nonnull)(void *, const void *, const void *)' [-Wincompatible-pointer-types]
                qsort_r(&arr->obj[ADBI_FIRST], adb_ra_num(arr), sizeof(arr->obj[0]), wacmp, &arg);
                                                                                            ^~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdlib.h:342:22: note: passing argument to parameter '__compar' here
            int (* _Nonnull __compar)(void *, const void *, const void *));
                            ^
../src/adb.c:995:81: warning: incompatible pointer types passing 'struct wacmp_param *' to parameter of type 'int (* _Nonnull)(void *, const void *, const void *)' [-Wincompatible-pointer-types]
                qsort_r(&arr->obj[ADBI_FIRST], adb_ra_num(arr), sizeof(arr->obj[0]), wadbcmp, &arg);
                                                                                              ^~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdlib.h:342:22: note: passing argument to parameter '__compar' here
            int (* _Nonnull __compar)(void *, const void *, const void *));
                            ^
2 warnings generated.
[5/6] Generating symbol file src/libapk.2.dylib.p/libapk.2.dylib.symbols