Problem loading libraries: libmpfr.so.4

Hi there! Yestearday, my Arduino IDE worked perfectly. But today, when I updated my computer, it gives to me the following error:

/usr/lib/gcc/avr/4.5.1/cc1: error while loading shared libraries: libmpfr.so.4: cannot open shared object file: No such file or directory

When I updated, pacman replaced the package "libsigc++2.0" with "libsigc++" (version 2.0). So, i thunk that's the problem.

How can i solve this??

Best regards ;D