Index: en_US.ISO8859-1/books/porters-handbook/uses/chapter.xml
===================================================================
--- en_US.ISO8859-1/books/porters-handbook/uses/chapter.xml
+++ en_US.ISO8859-1/books/porters-handbook/uses/chapter.xml
@@ -1144,15 +1144,21 @@
 	<xref linkend="go-libs"/> for more information.</para>
     </important>
 
-    <para>Possible arguments: (none),
-      <literal>modules</literal></para>
+    <para>Possible arguments: (none), <literal>build</literal>,
+      <literal>modules</literal>, <literal>run</literal></para>
 
     <para>Sets default values and targets used to build
-      <application>Go</application> software.  A build-time dependency
-      on <package role="port">lang/go</package> is added.  By default
-      the build is performed in GOPATH mode.  If Go software uses
-      modules, the modules-aware mode can be switched on with
-      <literal>modules</literal>.</para>
+      <application>Go</application> software.  A build dependency
+      on the Go port selected via <varname>GO_PORT</varname> is added.
+      By default the build is performed in GOPATH mode.  If Go
+      software uses modules, the modules-aware mode can be switched on
+      with <literal>modules</literal> argument.
+      <literal>build</literal> will setup build environment like
+      <varname>GO_ENV</varname>, <varname>GO_BUILDFLAGS</varname> but
+      skip creating <literal>post-extract</literal>,
+      <literal>do-build</literal> and <literal>do-install</literal>
+      targets.  <literal>run</literal> will also add run dependency on
+      whatever is in <varname>GO_PORT</varname>.</para>
 
     <para>The build process is controlled by several variables:</para>
 
@@ -1210,6 +1216,20 @@
 	<listitem>
 	  <para>Additional build arguments to be passed to
 	    <command>go install</command>.</para>
+	</listitem>
+      </varlistentry>
+
+      <varlistentry>
+	<term><varname>GO_PORT</varname></term>
+
+	<listitem>
+	  <para>The Go port to use.  By default this is
+	    <package role="port">lang/go</package> but can be set
+	    to <package role="port">lang/go-devel</package> in
+	    <literal>make.conf</literal> for testing with future Go
+	    versions.</para>
+	  <warning><para>This variable must not be set by individual
+	    ports!</para></warning>
 	</listitem>
       </varlistentry>
     </variablelist>