Compilation fails because of use of long long in OpenSSL

On a system with OpenSSL 1.0.0 I see

gcc -DPACKAGE_NAME=\"radsecproxy\" -DPACKAGE_TARNAME=\"radsecproxy\" -DPACKAGE_VERSION=\"1.6-dev\" -DPACKAGE_STRING=\"radsecproxy\ 1.6-dev\" -DPACKAGE_BUGREPORT=\"radsecproxy@uninett.no\" -DPACKAGE_URL=\"\" -DPACKAGE=\"radsecproxy\" -DVERSION=\"1.6-dev\" -DUSE_OPENSSL=1 -I. -g -Wall -Werror -fno-strict-aliasing -I/usr/local/include -I/usr/local/include/openssl -Wall -pedantic -pthread -DRADPROT_UDP -DRADPROT_TCP -DRADPROT_TLS -DRADPROT_DTLS -I /usr/local/include/nettle -MT radsecproxy.o -MD -MP -MF .deps/radsecproxy.Tpo -c -o radsecproxy.o radsecproxy.c
cc1: warnings being treated as errors
In file included from /usr/local/include/openssl/x509.h:107,
                 from /usr/local/include/openssl/ssl.h:156,
                 from radsecproxy.c:67:
/usr/local/include/openssl/sha.h:174: warning: ISO C90 does not support 'long long'
/usr/local/include/openssl/sha.h:175: warning: ISO C90 does not support 'long long'
/usr/local/include/openssl/sha.h:177: warning: ISO C90 does not support 'long long'

This is because we compile with -pedantic.