richard@deodand:~$ cat -n t.c
     1  static int x(char *f) {
     2   return *f;
     3  }
     4
     5  int y(char *f) {
     6   return *f;
     7  }
     8
     9  void z(const char *g) {
    10    int a;
    11    a = x((char *)g);
    12    a = y((char *)g);
    13  }
richard@deodand:~$ gcc-4.1 -Wall -O2 -c t.c
richard@deodand:~$ gcc-4.2 -Wall -O0 -c t.c
richard@deodand:~$ gcc-4.2 -Wall -O1 -c t.c
t.c: In function 'z':
t.c:11: warning: passing argument 1 of 'x' discards qualifiers from pointer target type



richard@deodand:~$ gcc-4.1 --version
gcc-4.1 (GCC) 4.1.3 20071019 (prerelease) (Debian 4.1.2-17)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

richard@deodand:~$ gcc-4.2 --version
gcc-4.2 (GCC) 4.2.3 20071014 (prerelease) (Debian 4.2.2-3)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

richard@deodand:~$ dpkg -l gcc-4.{1,2}
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name           Version        Description
+++-==============-==============-============================================
ii  gcc-4.1        4.1.2-17       The GNU C compiler
ii  gcc-4.2        4.2.2-3        The GNU C compiler