Syscall binding functions which use '__L4_INDIRECT_CALL' need to tell the
compiler that the 'edi' register gets modified. Since 'edi' is an input
operand and input operands may not get added to the clobber list, this
patch defines 'edi' also as an output operand instead.
Fixes#834.
With the update to L4ka::Pistachio, we no longer need to patch the
contrib sources. Our patch went upstream in the meanwhile.
Apparently, gcc-4.7 is picky about specifying the '-melf_i386' argument
at the command line of the GCC frontend. We need to make sure to use the
'-Wl,' prefix.
