windows/gdi: Remove.

This classic driver is so far behind Gallium softpipe/llvmpipe based
one, that's hard to imagine ever being useful.

v2: Drop drivers/windows from src/mesa/Makefile.am:EXTRA_DIST per Emil
Velikov.

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

v3: Update release notes.
diff --git a/docs/install.html b/docs/install.html
index b12e1cb..9dbfce5 100644
--- a/docs/install.html
+++ b/docs/install.html
@@ -127,14 +127,13 @@
 To build Mesa with SCons for Windows on Linux using the MinGW crosscompiler toolchain do
 </p>
 <pre>
-    scons platform=windows toolchain=crossmingw machine=x86 mesagdi libgl-gdi
+    scons platform=windows toolchain=crossmingw machine=x86 libgl-gdi
 </pre>
 <p>
 This will create:
 </p>
 <ul>
-<li>build/windows-x86-debug/mesa/drivers/windows/gdi/opengl32.dll &mdash; Mesa + swrast, binary compatible with Windows's opengl32.dll
-<li>build/windows-x86-debug/gallium/targets/libgl-gdi/opengl32.dll &mdash; Mesa + Gallium + softpipe, binary compatible with Windows's opengl32.dll
+<li>build/windows-x86-debug/gallium/targets/libgl-gdi/opengl32.dll &mdash; Mesa + Gallium + softpipe (or llvmpipe), binary compatible with Windows's opengl32.dll
 </ul>
 <p>
 Put them all in the same directory to test them.