This flag got lost in the move to mono.proj.
<_MonoConfigureParams Include="--disable-mcs-build" />
<_MonoConfigureParams Include="--disable-nls" />
<_MonoConfigureParams Include="--disable-visibility-hidden" />
+ <_MonoConfigureParams Include="--with-lazy-gc-thread-creation=yes" />
<_MonoConfigureParams Include="--enable-maintainer-mode" />
<_MonoConfigureParams Include="--enable-llvm-runtime"/>
<_MonoConfigureParams Include="--enable-icall-export"/>