lib/mkmf.rb (VPATH): use '&&' instead of 'and'.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4033 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/mkmf.rb

@@ -545,7 +545,7 @@ SHELL = /bin/sh
 srcdir = #{srcdir}
 topdir = #{$topdir}
 hdrdir = #{$hdrdir}
-VPATH = #{$mingw and CONFIG['build_os'] == 'cygwin' ? '$(shell cygpath -u $(srcdir))' : '$(srcdir)'}
+VPATH = #{$mingw && CONFIG['build_os'] == 'cygwin' ? '$(shell cygpath -u $(srcdir))' : '$(srcdir)'}
 }
   drive = File::PATH_SEPARATOR == ';' ? /\A\w:/ : /\A/
   if destdir = CONFIG["prefix"].scan(drive)[0] and !destdir.empty?