Fix DSO symbol test with MINGW64 and pedantic warnings

Fix DSO symbol test with MINGW64 and pedantic warnings

GetProcAddress() cannot be simple cast to void* (SD_SYM)
under strict warnigs, as it produces this
 error: ISO C forbids conversion of function pointer to
 object pointer type [-Werror=pedantic]

Use common trick with cast to (uintptr_t).

Reviewed-by: Tomas Mraz <tomas@openssl.foundation>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Norbert Pocs <norbertp@openssl.org>
MergeDate: Thu Apr 30 11:42:33 2026
(Merged from https://github.com/openssl/openssl/pull/30941)