Since gdb 7.4 setting breakpoint for a filepath containing spaces doesn't work anymore. See the following example:

niko@niko-home:~$ cat space\ spaces.c 
#include <stdio.h>

int tmp(void) {
    int a = 42;
    printf("%d", a);
}

int main(void) {
    tmp();

    return 0;
}

#gdb 7.3.1 works fine:
niko@niko-home:~$ gdb a.out 
GNU gdb (GDB) 7.3.1
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/niko/a.out...done.
(gdb) break "space spaces.c":4
Breakpoint 1 at 0x4004ec: file space spaces.c, line 4.
(gdb) r
Starting program: /home/niko/a.out 

Breakpoint 1, tmp () at space spaces.c:4
4           int a = 42;
(gdb) 


# gdb 7.4 doesn't:
niko@niko-home:~$ gdb a.out 
GNU gdb (GDB) 7.4
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/niko/a.out...done.
(gdb) break "space spaces.c":4
Breakpoint 1 at 0x4004ec: file space spaces.c, line 4.
(gdb) r
Starting program: /home/niko/a.out 
Error in re-setting breakpoint 1: Function "space spaces.c:4" not defined.
42[Inferior 1 (process 2008) exited normally]
(gdb)