bug#15944: 24.3.50; Compile mode does not detect error correctly

[Glenn Morris <rgm@gnu.org>]

Damien Merenne wrote:

> When running a C compilation using gcc > 4.7 where it also shows
> column numbers, errors are not detected correctly anymore. This seems
> to have been introduced with compile.el rev 111660:

I can't reproduce this with gcc 4.8.2, and it's hard to see how the
revision you cite could cause such a thing. Please give a complete
example starting from emacs -Q. Mine is:

cat /tmp/go.c:

int main ()
{
     x = 1;
     return 1;
}

emacs -Q -f compile
gcc /tmp/go.c RET

  -*- mode: compilation; default-directory: "~/" -*-
  Compilation started at Thu Nov 21 18:33:21
  
  gcc /tmp/go.c 
  /tmp/go.c: In function 'main':
  /tmp/go.c:3:6: error: 'x' undeclared (first use in this function)
        x = 1;
        ^
  /tmp/go.c:3:6: note: each undeclared identifier is reported only once for each function it appears in
  
  Compilation exited abnormally with code 1 at Thu Nov 21 18:33:21

The error and note are both correctly hyperlinked.