debian/README.source: Document the supported build profiles

debian/README.source

@@ -221,3 +221,15 @@ Example invocation:
         ../linux_4.2~rc6-1~exp2.dsc \
 	--timeout-test=1200 \
         --- adt-virt-qemu /var/cache/autopkgtest/adt-sid.img -o /var/tmp -c 2
+
+Build profiles
+==============
+
+Several build profiles are understood and supported:
+
+- stage1: Needed when bootstrapping an architecture.  A stage1 build
+  produces only the linux-libc-dev package and has no host
+  build-dependencies.
+- nodoc: Exclude most documentation
+- pkg.linux.notools: Exclude userland tool packages (linux-kbuild-<version>,
+  linux-perf-<version>, etc.)

debian/changelog

@@ -15,6 +15,7 @@ linux (4.7~rc2-1~exp1) UNRELEASED; urgency=medium
   * debian/rules.d/Makefile: Override architecture detection when building
     userland headers
   * linux-cpupower: Define PACKAGE_BUGREPORT to refer to reportbug, not upstream
+  * debian/README.source: Document the supported build profiles
 
  -- Ben Hutchings <ben@decadent.org.uk>  Tue, 07 Jun 2016 19:37:55 +0100