bix:~> cat t.c
int foo;
bar()
{
extern int foo;
}
bix:~> gcc -v
Reading specs from /usr/local/lib/gcc-lib/i586-pc-linux-gnu/2.96/specs
gcc version 2.96 20000221 (experimental)
bix:~> gcc -Wshadow -c t.c
t.c: In function `bar':
t.c:5: warning: declaration of `foo' shadows global declaration