private module functions: misleading error message

[Daniel Franke]

A few minutes ago, I wrote:
> $>  gfortran-4.1.1 -g -Wall -Wno-implicit foo.f90
>  In file foo.f90:11
>
>   IF ( foozerize() ) THEN
>       1

The -Wno-implicit was wrong here. Should have
been-Wimplicit-interface", then  gfortran complains about the missing
interface also:

$> gfortran -g -Wall -Wimplicit-interface foo.f90
 In file foo.f90:11

  IF ( foozerize() ) THEN
      1
Warning: Procedure 'foozerize' called with an implicit interface at (1)
 In file foo.f90:11

  IF ( foozerize() ) THEN
      1
Error: ELSE IF clause at (1) requires a scalar LOGICAL expression