Absolutized paths involving the scala package.

Confusing, now-it-happens now-it-doesn't mysteries lurk
in the darkness. When scala packages are declared like this:

  package scala.collection.mutable

Then paths relative to scala can easily be broken via the unlucky
presence of an empty (or nonempty) directory. Example:

  // a.scala
  package scala.foo
  class Bar { new util.Random }

  % scalac ./a.scala
  % mkdir util
  % scalac ./a.scala
  ./a.scala:4: error: type Random is not a member of package util
    new util.Random
             ^
  one error found

There are two ways to play defense against this:

 - don't use relative paths; okay sometimes, less so others
 - don't "opt out" of the scala package

This commit mostly pursues the latter, with occasional doses
of the former.

I created a scratch directory containing these empty directories:

  actors annotation ant api asm beans cmd collection compat
  concurrent control convert docutil dtd duration event factory
  forkjoin generic hashing immutable impl include internal io
  logging macros man1 matching math meta model mutable nsc parallel
  parsing partest persistent process pull ref reflect reify remote
  runtime scalap scheduler script swing sys text threadpool tools
  transform unchecked util xml

I stopped when I could compile the main src directories
even with all those empties on my classpath.

Author: paulp

src/library/scala/xml/Atom.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** The class `Atom` provides an XML node for text (`PCDATA`).
  *  It is used in both non-bound and bound XML representations.

src/library/scala/xml/Attribute.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** This singleton object contains the `apply` and `unapply` methods for
  *  convenient construction and deconstruction.

src/library/scala/xml/Comment.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** The class `Comment` implements an XML node for comments.
  *

src/library/scala/xml/Document.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** A document information item (according to InfoSet spec). The comments
  *  are copied from the Infoset spec, only augmented with some information

src/library/scala/xml/Elem.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** This singleton object contains the `apply` and `unapplySeq` methods for
  *  convenient construction and deconstruction. It is possible to deconstruct

src/library/scala/xml/EntityRef.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** The class `EntityRef` implements an XML node for entity references.
  *

src/library/scala/xml/Equality.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** In an attempt to contain the damage being inflicted on consistency by the
  *  ad hoc `equals` methods spread around `xml`, the logic is centralized and

src/library/scala/xml/Group.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** A hack to group XML nodes in one node for output.
  *

src/library/scala/xml/MalformedAttributeException.scala

@@ -8,7 +8,8 @@
 
 
 
-package scala.xml
+package scala
+package xml
 
 
 case class MalformedAttributeException(msg: String) extends RuntimeException(msg)

src/library/scala/xml/MetaData.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import Utility.sbToString
 import scala.annotation.tailrec

src/library/scala/xml/NamespaceBinding.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import Utility.sbToString
 

src/library/scala/xml/Node.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** This singleton object contains the `unapplySeq` method for
  *  convenient deconstruction.

src/library/scala/xml/NodeBuffer.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /**
  * This class acts as a Buffer for nodes. If it is used as a sequence of

src/library/scala/xml/NodeSeq.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import scala.collection.{ mutable, immutable, generic, SeqLike, AbstractSeq }
 import mutable.{ Builder, ListBuffer }

src/library/scala/xml/Null.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import Utility.isNameStart
 import scala.collection.Iterator

src/library/scala/xml/PCData.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** This class (which is not used by all XML parsers, but always used by the
  *  XHTML one) represents parseable character data, which appeared as CDATA

src/library/scala/xml/PrefixedAttribute.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 
 /** prefixed attributes always have a non-null namespace.
  *

src/library/scala/xml/PrettyPrinter.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import Utility.sbToString
 

src/library/scala/xml/ProcInstr.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 
 /** an XML node for processing instructions (PI)
  *

src/library/scala/xml/QNode.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** This object provides an extractor method to match a qualified node with
  *  its namespace URI

src/library/scala/xml/SpecialNode.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** `SpecialNode` is a special XML node which represents either text
  *  `(PCDATA)`, a comment, a `PI`, or an entity ref.

src/library/scala/xml/Text.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** The class `Text` implements an XML node for text (PCDATA).
  *  It is used in both non-bound and bound XML representations.

src/library/scala/xml/TextBuffer.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 
 import Utility.isSpace
 

src/library/scala/xml/TopScope.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 
 /** top level namespace scope. only contains the predefined binding
  *  for the "xml" prefix which is bound to

src/library/scala/xml/TypeSymbol.scala

@@ -8,7 +8,8 @@
 
 
 
-package scala.xml
+package scala
+package xml
 
 
 abstract class TypeSymbol

src/library/scala/xml/Unparsed.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 /** An XML node for unparsed content. It will be output verbatim, all bets
  *  are off regarding wellformedness etc.

src/library/scala/xml/UnprefixedAttribute.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 
 /** Unprefixed attributes have the null namespace, and no prefix field
  *

src/library/scala/xml/Utility.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import scala.collection.mutable
 import parsing.XhtmlEntities

src/library/scala/xml/XML.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 
 import parsing.NoBindingFactoryAdapter
 import factory.XMLLoader

src/library/scala/xml/Xhtml.scala

@@ -1,5 +1,6 @@
 
-package scala.xml
+package scala
+package xml
 
 import parsing.XhtmlEntities
 import Utility.{ sbToString, isAtomAndNotText }

src/library/scala/xml/dtd/ContentModel.scala

@@ -6,9 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-
-
-package scala.xml
+package scala
+package xml
 package dtd
 
 import scala.xml.dtd.impl._

src/library/scala/xml/dtd/ContentModelParser.scala

@@ -6,7 +6,8 @@
 **                          |/                                          **
 \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 /** Parser for regexps (content models in DTD element declarations) */

src/library/scala/xml/dtd/DTD.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 import scala.collection.mutable

src/library/scala/xml/dtd/Decl.scala

@@ -6,7 +6,8 @@
  **                          |/                                          **
  \*                                                                      */
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 import Utility.sbToString

src/library/scala/xml/dtd/DocType.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 /** An XML node for document type declaration.

src/library/scala/xml/dtd/ElementValidator.scala

@@ -8,7 +8,8 @@
 
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 import PartialFunction._

src/library/scala/xml/dtd/ExternalID.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 /** an ExternalIDs - either PublicID or SystemID

src/library/scala/xml/dtd/Scanner.scala

@@ -7,7 +7,8 @@
 \*                                                                      */
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 /** Scanner for regexps (content models in DTD element declarations)

src/library/scala/xml/dtd/Tokens.scala

@@ -8,7 +8,8 @@
 
 
 
-package scala.xml
+package scala
+package xml
 package dtd
 
 

src/library/scala/xml/dtd/ValidationException.scala

@@ -8,7 +8,8 @@
 
 
 
-package scala.xml
+package scala
+package xml
 package dtd