Core Tor 0.4.5.6 claims "OpenSSL has been built without thread support" on static Mingw build

Building on Linux for static win32 and win64. This didn't happen on previous versions, which built correctly with same OpenSSL. Also, this error arises on make step, configure doesn't report any problem:

src/lib/crypt_ops/crypto_openssl_mgt.c:135:2: error: #error "OpenSSL has been built without thread support. Tor requires an OpenSSL library with thread support enabled."
[...]
make[1]:*** [Makefile:16657: src/lib/crypt_ops/libtor_crypt_ops_a-crypto_openssl_mgt.o] Error 1