Update the documentation for meson

Meson is pretty well tested and works in most configurations now, so we
can remove the warning about it being unsuited for actual use.

It's also worth documenting that meson 0.42.0 or greater is required.

v2: - Minor rewording of supported platforms as suggested by Emil
    - Add two missing tags as reported by xmllint --html

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com> (v1)
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com> (v1)

docs/meson.html

@@ -18,11 +18,20 @@
 
 <h2 id="basic">1. Basic Usage</h2>
 
-<p><strong>The Meson build system for Mesa is still under active development,
+<p><strong>The Meson build system is generally considered stable and ready
-and should not be used in production environments.</strong></p>
+for production</strong></p>
 
-<p>The meson build is currently only tested on linux, and is known to not work
+<p>The meson build is tested on on Linux, macOS, Cygwin and Haiku, it should
-on macOS, Windows, and haiku. This will be fixed.</p>
+work on FreeBSD, DragonflyBSD, NetBSD, and OpenBSD.</p>
+
+<p><strong>Mesa requires Meson >= 0.42.0 to build in general.</strong>
+
+Additionaly, to build the Clover OpenCL state tracker or the OpenSWR driver
+meson 0.44.0 or greater is required.
+
+Some older versions of meson do not check that they are too old and will error
+out in odd ways.
+</p>
 
 <p>
 The meson program is used to configure the source directory and generates
@@ -111,6 +120,7 @@ change compiler in a configured build directory.
 </dd>
 
 
+<dl>
 <dt><code>LLVM</code></dt>
 <dd><p>Meson includes upstream logic to wrap llvm-config using it's standard
 dependncy interface. It will search $PATH (or %PATH% on windows) for
@@ -119,15 +129,15 @@ llvm-config, so using an LLVM from a non-standard path is as easy as
 </p></dd>
 </dl>
 
+<dl>
 <dt><code>PKG_CONFIG_PATH</code></dt>
 <dd><p>The
 <code>pkg-config</code> utility is a hard requirement for configuring and
-building Mesa on Linux and *BSD. It is used to search for external libraries
+building Mesa on Unix-like systems. It is used to search for external libraries
-on the system. This environment variable is used to control the search
+on the system. This environment variable is used to control the search path for
-path for <code>pkg-config</code>. For instance, setting
+<code>pkg-config</code>. For instance, setting
-<code>PKG_CONFIG_PATH=/usr/X11R6/lib/pkgconfig</code> will search for
+<code>PKG_CONFIG_PATH=/usr/X11R6/lib/pkgconfig</code> will search for package
-package metadata in <code>/usr/X11R6</code> before the standard
+metadata in <code>/usr/X11R6</code> before the standard directories.</p>
-directories.</p>
 </dd>
 </dl>
 
@@ -151,9 +161,9 @@ may interfer with debbugging as some code and validation will be optimized
 away.
 </p>
 
-<p> For those wishing to pass their own -O option, use the "plain" buildtype,
+<p> For those wishing to pass their own optimization flags, use the "plain"
-which cuases meson to inject no additional compiler arguments, only those in
+buildtype, which causes meson to inject no additional compiler arguments, only
-the C/CXXFLAGS and those that mesa itself defines.</p>
+those in the C/CXXFLAGS and those that mesa itself defines.</p>
 </dd>
 </dl>