Update INSTALL.md for meson

Author: drobilla

INSTALL

@@ -0,0 +1,74 @@
+Installation Instructions
+=========================
+
+Prerequisites
+-------------
+
+To build from source, you will need:
+
+ * A relatively modern C++ compiler (GCC, Clang, and MSVC are known to work).
+
+ * [Meson](http://mesonbuild.com/), which depends on
+   [Python](http://python.org/).
+
+This is a brief overview of building this project with meson.  See the meson
+documentation for more detailed information.
+
+Configuration
+-------------
+
+The build is configured with the `setup` command, which creates a new build
+directory with the given name:
+
+    meson setup build
+
+Some environment variables are read during `setup` and stored with the
+configuration:
+
+  * `CXX`: Path to C++ compiler.
+  * `CXXFLAGS`: C++ compiler options.
+  * `LDFLAGS`: Linker options.
+
+However, it is better to use meson options for configuration.  All options can
+be inspected with the `configure` command from within the build directory:
+
+    cd build
+    meson configure
+
+Options can be set by passing C-style "define" options to `configure`:
+
+    meson configure -Dcpp_args="-march=native" -Dprefix="/opt/mypackage/"
+
+Note that some options, such as `strict` and `werror` are for
+developer/maintainer use only.  Please don't file issues about anything that
+happens when they are enabled.
+
+Building
+--------
+
+From within a configured build directory, everything can be built with the
+`compile` command:
+
+    meson compile
+
+Similarly, tests can be run with the `test` command:
+
+    meson test
+
+Meson can also generate a project for several popular IDEs, see the `backend`
+option for details.
+
+Installation
+------------
+
+A compiled project can be installed with the `install` command:
+
+    meson install
+
+You may need to acquire root permissions to install to a system-wide prefix.
+For packaging, the installation may be staged to a directory using the
+`DESTDIR` environment variable or the `--destdir` option:
+
+    DESTDIR=/tmp/mypackage/ meson install
+
+    meson install --destdir=/tmp/mypackage/