Backport change from 1.1.13: src/Makefile.am: Use wx-config's --rescomp option to get the command and options needed to turn .rc files into object files.
git-svn-id: file:///home/survex-svn/survex/branches/1.0@3472 4b37db11-9a0c-4f06-9ece-9ab7cdaee568
