Modern cygwin often has empty $ENV{CYGWIN}

Fixes Use of uninitialized value $ENV{"CYGWIN"} in concatenation (.) or string
at /usr/lib/perl5/5.13.10/i686-cygwin/Config_heavy.pl line 54

1 files changed, 1 insertions, 1 deletions

diff --git a/configpm b/configpm
index 3427f36c22..7d6de3721e 100755
--- a/configpm
+++ b/configpm
@@ -203,7 +203,7 @@ sub _V {
     print "  $date\n" if defined $date;
 
     my @env = map { "$_=\"$ENV{$_}\"" } sort grep {/^PERL/} keys %ENV;
-    push @env, "CYGWIN=\"$ENV{CYGWIN}\"" if $^O eq 'cygwin';
+    push @env, "CYGWIN=\"$ENV{CYGWIN}\"" if $^O eq 'cygwin' and $ENV{CYGWIN};
 
     if (@env) {
         print "  \%ENV:\n";