Add Go frontend, libgo library, and Go testsuite.

gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407

libgo/go/archive/zip/struct.go

@@ -0,0 +1,33 @@
+package zip
+
+const (
+	fileHeaderSignature      = 0x04034b50
+	directoryHeaderSignature = 0x02014b50
+	directoryEndSignature    = 0x06054b50
+)
+
+type FileHeader struct {
+	Name             string
+	CreatorVersion   uint16
+	ReaderVersion    uint16
+	Flags            uint16
+	Method           uint16
+	ModifiedTime     uint16
+	ModifiedDate     uint16
+	CRC32            uint32
+	CompressedSize   uint32
+	UncompressedSize uint32
+	Extra            []byte
+	Comment          string
+}
+
+type directoryEnd struct {
+	diskNbr            uint16 // unused
+	dirDiskNbr         uint16 // unused
+	dirRecordsThisDisk uint16 // unused
+	directoryRecords   uint16
+	directorySize      uint32
+	directoryOffset    uint32 // relative to file
+	commentLen         uint16
+	comment            string
+}