Fix mysqld crash on s390x that stemmed from WolfSSL
The mysqld binary was crashing on s390x with the following stack trace: stack_bottom = 0x0 thread_stack 0x49000 /<<PKGBUILDDIR>>/builddir/sql/mysqld(my_print_stacktrace+0x2a)[0x12afc293a] mysys/stacktrace.c:270(my_print_stacktrace)[0x12a9c7ca4] [0x3ffed0f3f0e] sql/signal_handler.cc:209(handle_fatal_signal)[0x12af9dfce] src/tfm.c:3642(fp_copy)[0x12af9fa8c] src/tfm.c:1601(_fp_exptmod)[0x12afa044e] src/tfm.c:2277(fp_exptmod)[0x12afa0aa0] src/tfm.c:4021(fp_prime_miller_rabin_ex)[0x12afa10f6] src/tfm.c:4283(mp_prime_is_prime_ex)[0x12af8393a] src/dh.c:2108(_DhSetKey)[0x12af844b6] src/dh.c:2154(wc_DhSetCheckKey)[0x12af2dade] src/ssl.c:1744(wolfSSL_CTX_SetTmpDH)[0x12af5083e] src/ssl.c:38473(wolfSSL_CTX_set_tmp_dh)[0x12b025eba] vio/viosslfactories.c:340(new_VioSSLFd)[0x12b0260cc] vio/viosslfactories.c:413(new_VioSSLAcceptorFd)[0x12a6cab58] /lib/s390x-linux-gnu/libc.so.6(__libc_start_main+0x10a)[0x3ff88f2a90a] /<<PKGBUILDDIR>>/builddir/sql/mysqld(+0x5bcae4)[0x12a6bcae4] [0x0] From analysis by Marko Mäkelä: The pointer that _fp_exptmod() is passing as the first parameter of fp_copy() is bad on this architecture for some reason. It seems to me that adding -DWC_NO_CACHE_RESISTANT to the CMAKE_C_FLAGS on this architecture could address the problem.