doc/guide/install: archlinux: list required libraries to build from source

doc/guide/install.rst

@@ -15,6 +15,14 @@ openFPGALoader is available in the default repositories:
 
     sudo pacman -S openfpgaloader
 
+Alternatively, you could build from source. First: install required libraries:
+
+.. code-block:: bash
+
+   sudo pacman -S git cmake make gcc pkgconf libftdi libusb zlib hidapi
+
+Build step is similar as Debian
+
 Fedora
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