When generating Go code, make -cgo the default.

Add new -no-cgo option to disable the default.
Keep -cgo as a no-op for existing users.

Doc/Manual/Go.html

@@ -125,16 +125,15 @@ Go distribution.  To generate code for gccgo, you should also use the
 </p>
 
 <p>
-When using the <tt>-cgo</tt> option, SWIG will generate files that can be used
-directly by <tt>go build</tt>.  Starting with the Go 1.5 distribution the
-<tt>-cgo</tt> option has to be given.  Put your SWIG interface file in a
-directory under GOPATH/src, and give it a name that does <b>not</b> end in the
-.swig or .swigcxx extension.  Typically the SWIG interface file extension is .i
-in this case.
+By default SWIG will generate files that can be used directly
+by <tt>go build</tt>.  This requires Go 1.2 or later.  Put your SWIG
+interface file in a directory under GOPATH/src, and give it a name
+that does <b>not</b> end in the .swig or .swigcxx extension.
+Typically the SWIG interface file extension is .i in this case.
 </p>
 
 <div class="code"><pre>
-% swig -go -cgo example.i
+% swig -go example.i
 % go install
 </pre></div>
 
@@ -144,15 +143,16 @@ usual.
 </p>
 
 <p>
-To use SWIG without the <tt>-cgo</tt> option, more steps are required.  Recall
-that this only works with Go versions before 1.5.  When using Go version 1.2 or
-later, or when using gccgo, the code generated by SWIG can be linked directly
-into the Go program.  A typical command sequence when using the Go compiler of
-the Go distribution would look like this:
+SWIG can be used without cgo, via the <tt>-no-cgo</tt> option, but
+more steps are required.  This only works with Go versions before 1.5.
+When using Go version 1.2 or later, or when using gccgo, the code
+generated by SWIG can be linked directly into the Go program.  A
+typical command sequence when using the Go compiler of the Go
+distribution would look like this:
 </p>
 
 <div class="code"><pre>
-% swig -go example.i
+% swig -go -no-cgo example.i
 % gcc -c code.c    # The C library being wrapped.
 % gcc -c example_wrap.c
 % go tool 6g example.go
@@ -169,7 +169,7 @@ sequence for this approach would look like this:
 </p>
 
 <div class="code"><pre>
-% swig -go -use-shlib example.i
+% swig -go -no-cgo -use-shlib example.i
 % gcc -c -fpic example.c
 % gcc -c -fpic example_wrap.c
 % gcc -shared example.o example_wrap.o -o example.so
@@ -200,10 +200,15 @@ swig -go -help
 
 <tr>
 <td>-cgo</td>
-<td>Generate files to be used as input for the Go cgo tool.  This
-  option is required for Go 1.5 and later, and works for Go 1.2 and
-  later.  In the future this option will likely become the
-  default.</td>
+<td>Generate files to be used as input for the Go cgo tool.  This is
+  the default.</td>
+</tr>
+
+<tr>
+<td>-no-cgo</td>
+<td>Generate files that can be used directly, rather than via the Go
+  cgo tool.  This option does not work with Go 1.5 or later.  It is
+  required for versions of Go before 1.2.</td>
 </tr>
 
 <tr>
@@ -268,11 +273,11 @@ swig -go -help
 
 
 <p>There are two different approaches to generating wrapper files,
-  controlled by SWIG's <tt>-cgo</tt> option.  The <tt>-cgo</tt> option
-  works with Go version 1.2 or later.  It is required when using Go
-  version 1.5 or later.</p>
+  controlled by SWIG's <tt>-no-cgo</tt> option.  The <tt>-no-cgo</tt>
+  option only works with version of Go before 1.5.  It is required
+  when using versions of Go before 1.2.</p>
 
-<p>With or without the <tt>-cgo</tt> option, SWIG will generate the
+<p>With or without the <tt>-no-cgo</tt> option, SWIG will generate the
   following files when generating wrapper code:</p>
 
 <ul>
@@ -296,8 +301,8 @@ or C++ compiler.
 </li>
 </ul>
 
-<p>When neither the <tt>-cgo</tt> nor the <tt>-gccgo</tt> option is
-  used, SWIG will also generate an additional file:</p>
+<p>When the <tt>-no-cgo</tt> option is used, and the <tt>-gccgo</tt>
+  option is not used, SWIG will also generate an additional file:</p>
 
 <ul>
 <li>