[perl-ExtUtils-Depends] Add comments for find_extra_libs method (closes RT#43900)

[Brian Manning <bmanning src gnome org>]

commit 043ea929296964315d903725b13ec8c1670ffaa6
Author: Brian Manning <bmanning src gnome org>
Date:   Sun Jul 28 16:03:38 2013 -0700

    Add comments for find_extra_libs method (closes RT#43900)

 lib/ExtUtils/Depends.pm |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/lib/ExtUtils/Depends.pm b/lib/ExtUtils/Depends.pm
index 6d66990..c344d01 100644
--- a/lib/ExtUtils/Depends.pm
+++ b/lib/ExtUtils/Depends.pm
@@ -306,6 +306,9 @@ sub build_dll_lib {
                '$(INST_ARCHAUTODIR)/$(BASEEXT)$(LIB_EXT)';
 }
 
+# Search for extra library files to link against on Windows (either native
+# Windows library # files, or Cygwin library files)
+# NOTE: not meant to be called publicly, so no POD documentation
 sub find_extra_libs {
        my $self = shift;