[scons] only apply FreeBSD11 workaround on FreeBSD
[scons] only apply FreeBSD11 workaround on FreeBSD

lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,PatchyFog/lighttpd1.4-mbedtls,PatchyFog/lighttpd1.4-mbedtls,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,lighttpd/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,PatchyFog/lighttpd1.4-mbedtls