or Things to do before you install InkScape
after installing libs, (as root) you need to run ldconfig so that the linker can find the libraries that you have just installed. If you aren't logged in as root (i.e. if you became root by typing su) you may not have the /sbin/ directory in your path. so if ldconfig isn't working for you try typing /sbin/ldconfig
download and install the latest version of libgc[]
libgc installs in /usr/local/lib by default. If you have installed it and it is still not linking, you may not have that in your library path. There is a LD_LIBRARY_PATH environment variable, or alternatively you can make sure that /usr/local/lib is listed in the file /etc/ls.so.conf
download and install libsig++ 
this should be fairly straightforward.