[gnome-builder/wip/tintou/sysroot: 18/20] doc: add sysroot configuration to the documentation

[Corentin Noël <corentinnoel src gnome org>]

commit e8ea5816ebdd27e0be7f76dcd3aac50e1772415b
Author: Corentin Noël <corentin noel collabora co uk>
Date:   Thu Feb 22 15:35:48 2018 +0000

    doc: add sysroot configuration to the documentation

 doc/help/howto/index.rst   |  1 +
 doc/help/howto/sysroot.rst | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+)
---
diff --git a/doc/help/howto/index.rst b/doc/help/howto/index.rst
index 4a7ebe5c4..ebe0a3518 100644
--- a/doc/help/howto/index.rst
+++ b/doc/help/howto/index.rst
@@ -17,3 +17,4 @@ Contents
    jump_to_definition
    search_for_symbol
    rust_integration
+   sysroot
diff --git a/doc/help/howto/sysroot.rst b/doc/help/howto/sysroot.rst
new file mode 100644
index 000000000..60b27b973
--- /dev/null
+++ b/doc/help/howto/sysroot.rst
@@ -0,0 +1,22 @@
+####################
+Use a Custom Sysroot
+####################
+
+If you need to use a custom sysroot. You can configure a new target in `Preferences->SDKs`.
+
+There are three fields to fill:
+
+- Name: The name of your choice describing this sysroot.
+- Sysroot path: The absolute path on your filesystem leading to the sysroot.
+- Additional pkg-config path: (optional) A colon separated list of absolute path leading to pkg-config 
folders of the sysroot.
+
+.. note:: By default pkg-config will search in /lib/pkgconfig and /usr/lib/pkgconfig but some systems are 
installing them in different directories (for instance a x86_64 Debian-based system will require 
/usr/lib/x86_64-linux-gnu/pkgconfig when a RPM-based system will use /usr/lib64/pkgconfig).
+
+The configuration will be stored in ~/.config/gnome-builder/sysroot/general.conf using a simple key-value 
format:
+
+.. code-block:: cfg
+
+    [Sysroot 0]
+    Name=My Sysroot 😎
+    Path=/path/to/my_sysroot
+    PkgConfigPath=/path/to/my_sysroot/usr/lib/x86_64-linux-gnu/pkgconfig