using shared runtime and phobos

[ketmar]

can i tell gdc to build and use shared druntime and phobos 
libraries? it's ok for me to install gdc system-wide, and i don't 
like huge compiled D binaries which won't share the same code.

i tried '--enable-shared', but it have no effect.
is there any configure option to force gdc to build and use 
libdruntime.so and libphobos2.so instead of *.a?

i'm using gcc 4.8.2.