Update misc.c

Line 96:
 fprintf(stderr, linenum ? "%s: %i: " : "%s: ", filename, linenum);
will cause compilation on osx to fail with:
cc -g -Wall -Werror -O2  -Iobj -oobj/misc.o -c src/misc.c
src/misc.c:95:66: error: data argument not used by format string [-Werror,-Wformat-extra-args]
        fprintf(stderr, linenum ? "%s: %i: " : "%s: ", filename, linenum);

Proposing change to:
 linenum ? fprintf(stderr, "%s: %i: ", filename, linenum) : fprintf(stderr, "%s: ", filename);
Merge pull request #9 from mlasak/patch-1

Fix compilation bug on OSX