[perl #42218] [PATCH][Cygwin] Use bc on Cygwin

[via RT]

# New Ticket Created by  Ron Blaschke 
# Please include the string:  [perl #42218]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=42218 >


Attached patch enables bc on Cygwin (if available).  Also, if bc is 
skipped Configure says so, instead of just 'no'.

Index: config/auto/bc.pm
===================================================================
--- config/auto/bc.pm   (revision 17857)
+++ config/auto/bc.pm   (working copy)
@@ -41,6 +41,7 @@
     my %bc_does_not_hang = (
         linux   => 1,
         MSWin32 => 1,
+        cygwin  => 1,
     );
 
     if ( $bc_does_not_hang{$osname} ) {
@@ -49,13 +50,15 @@
         my $answer = capture_output( 'bc', '-v' ) || '';
         $has_gnu_bc = ( $answer =~ m/^bc / && $answer =~ m/Free Software 
Foundation/ ) ? 1 : 0;
 
+        $self->set_result( $has_gnu_bc ? 'yes' : 'no' );
     }
     else {
         $has_gnu_bc = 0;
+
+        $self->set_result( 'skipped (platform)' );
     }
 
     $conf->data->set( has_gnu_bc => $has_gnu_bc );
-    $self->set_result( $has_gnu_bc ? 'yes' : 'no' );
 
     return $self;
 }