README: Rework section on configuring, building and testing

Also note how to install recent versions of meson, for those whose
distros tend to be behind the times.

Change-Id: I43c3ded89e7d6d66c0968565908545f423f05a5c
Signed-off-by: Andrew Jeffery <[email protected]>

Author: amboar

README.md

@@ -32,18 +32,25 @@ The library also provides API to pack and unpack PLDM headers.
 
 ## To Build
 
-Need `meson` and `ninja`. Alternatively, source an OpenBMC ARM/x86 SDK.
+`libpldm` is configured and built using `meson`. Python's `pip` or
+[`pipx`][pipx] can be used to install a recent version on your machine:
+
+[pipx]: https://pipx.pypa.io/latest/
 
 ```sh
-meson setup builddir && ninja -C builddir
+pipx install meson
 ```
 
-## To run unit tests
+Once `meson` is installed:
+
+```sh
+meson setup build && meson compile -C build
+```
 
-The simplest way of running the tests is as described by the meson man page:
+## To run unit tests
 
 ```sh
-meson setup builddir && meson test -C builddir
+meson test -C build
 ```
 
 ## Working with `libpldm`