Introduce an (arbitrary) ordering for extra pages

blog/content/extra/_index.md

@@ -2,4 +2,5 @@
 title = "Extra Content"
 insert_anchor = "left"
 render = false
+sort_by = "order"
 +++

blog/content/extra/cross-compile-binutils.md

@@ -2,6 +2,7 @@
 title = "Cross Compile Binutils"
 template = "plain.html"
 url = "cross-compile-binutils"
+order = 2
 +++
 
 The [GNU Binutils] are a collection of various binary tools such as `ld`, `as`, `objdump`, or `readelf`. These tools are platform-specific, so you need to compile them again if your host system and target system are different. In our case, we need `ld` and `objdump` for the x86_64 architecture.

blog/content/extra/cross-compile-libcore.md

@@ -2,6 +2,7 @@
 title = "Cross Compiling: libcore"
 template = "plain.html"
 url = "cross-compile-libcore"
+order = 3
 +++
 
 If you get an `error: can't find crate for 'core'`, you're probably compiling for a different target (e.g. you're passing the `target` option to `cargo build`). Now the compiler complains that it can't find the `core` library. This document gives a quick overview how to fix this problem. For more details, see the [rust-cross] project.

blog/content/extra/set-up-gdb/index.md

@@ -2,6 +2,7 @@
 title = "Set Up GDB"
 template = "plain.html"
 url = "set-up-gdb"
+order = 4
 +++
 
 There are a lot of things that can go wrong when developing an OS. So it's a good idea to add a debugger to our toolset, which allows us to set breakpoints and examine variables. We will use [GDB](https://www.gnu.org/software/gdb/) as QEMU supports it out of the box.

blog/content/extra/talks.md

@@ -2,6 +2,7 @@
 title = "Talks"
 url = "talks"
 template = "plain.html"
+order = 1
 +++
 
 - “Open Source OS Development in Rust” at HTWG Konstanz, May 22, 2017: [slides](https://phil-opp.github.io/talk-konstanz-may-2017/)