Description of problem:
Cproto segfaults when reading from stdin.

Version-Release number of selected component (if applicable):
Name   : cproto
Arch   : x86_64
Version: 4.7e
Release: 2.fc6

How reproducible:
Every time.

Steps to Reproduce:
1. Run the following command:
$ echo "#include <stdio.h>
int main(int argc, char *argv[]) { printf(\"hello world\n\"); }" | cproto

  

Additional info:
- I have not yet tested this on my i386 laptop, only on my x86_64 workstation.
- This works just fine:
$ echo "#include <stdio.h>
int main(int argc, char *argv[]) { printf(\"hello world\n\"); }" >hello.c;
cproto hello.c
- gdb backtrace:
Program received signal SIGSEGV, Segmentation fault.
0x0000000000407439 in get_cpp_directive (copy=1) at ./lex.l:726
726             *temp_buf = '\0';
(gdb) backtrace 
#0  0x0000000000407439 in get_cpp_directive (copy=1) at ./lex.l:726
#1  0x00000000004080c3 in yylex () at ./lex.l:175
#2  0x0000000000409709 in yyparse () at y.tab.c:877
#3  0x000000000040acdb in process_file (infile=<value optimized out>,
name=0x40b65d "stdin") at ./grammar.y:1011
#4  0x0000000000402348 in main (argc=1, argv=0x7fff97c14078) at cproto.c:821
#5  0x000000373681dab4 in __libc_start_main (main=0x401910 <main>, argc=1,
ubp_av=0x7fff97c14078, 
    init=<value optimized out>, fini=<value optimized out>, rtld_fini=<value
optimized out>, 
    stack_end=0x7fff97c14068) at libc-start.c:222
#6  0x00000000004012c9 in _start ()