Create Compiling (doc for new release Makefile)

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+This page is about compiling the sources included in [stable](https://xonotic.org/download) and [beta](https://beta.xonotic.org/autobuild) releases, and is also applicable when updating by rsync.  
+For development purposes, please see [Repository_Access](Repository_Access).
+
+The release Makefile aims to provide a convenient way to compile for alternative CPU architectures, or to get a build fully optimised for a recent x86 CPU (the official binaries are generic x86_64).  To this end the Makefile defaults to enabling all optimisations that can be used on your current CPU without causing bugs, and to using all available CPU threads.
+
+The builds will be mostly dynamically linked, except for d0_blind_id which is statically linked to ensure reliable player ID support and because distributions don't ship this.
+
+Invoking `make` or `make help` will print the supported targets and config.  
+
+Most people reading this will want `make update-beta; make client`.  
+
+## Build Dependencies
+### Debian
+`build-essential automake libgmp-dev libjpeg-dev libpng-dev libcurl-dev libsdl2-dev`  
+*note that Debian's `libjpeg-dev` depends on `libjpeg62-turbo-dev`*