Can't use '::' with isspace

[Tron Thomas]

I tried using the following command:

g++ -Wall -o foo foo.cpp

on the following file (foo.cpp):

#include <ctype.h>

int main(void)
{
    ::isspace(32);
}

This produces the following results:

foo.cpp: In function `int main()':
foo.cpp:5: parse error before `('

If I remove the double colons '::' before the call to isspace the
program will compile without errors.  I compiled the program as a
C++ program, so the double colons before the function call should be
valid.  This  appears to be a bug with the GNU C++ compiler.