Update README

README.md

@@ -70,12 +70,22 @@ using root privileges and sudo, simply run:
 # Building with meson + ninja
 
 The sys/install.sh method uses acr+make to build r2 from sources, which is the default
-and recommended way, but there's also a work-in-progress support for Meson. Here's how
-to build r2 with meson and ninja (supports linux, mac and windows)
+and recommended way, but there's also a work-in-progress support for Meson.
 
-	$ make meson            # will run make meson-config automatically
-	$ make meson-symstall   # symstall the meson build into PREFIX (/usr)
-	$ make meson-uninstall  # uninstall the meson installation
+You can install last version of meson and ninja using r2pm:
+
+	$ r2pm -i meson
+	$ r2pm -r make meson
+	$ r2pm -r make meson-symstall
+
+Or just run those lines if you have them available in PATH:
+
+	$ make meson                # will run make meson-config automatically
+	$ sudo make meson-symstall  # symstall the meson build into PREFIX (/usr)
+	$ sudo make meson-uninstall # uninstall the meson installation
+
+The PREFIX is inherited from the last run of ./configure, so it's recommended to run
+sys/install.sh at least once to autodetect this, this step will end up into meson.
 
 At the moment, the meson build system doesnt supports much configuration options and it
 is not able to build all the plugins, it has been tested to work on the following hosts: