_posts: post about host arch flag

for void-linux/void-packages#46263

Author: classabbyamp

_posts/2024-01-22-xbps-src-host-arch.md

@@ -0,0 +1,43 @@
+---
+title: Changes to xbps-src Masterdir Creation and Use
+layout: post
+---
+
+In an effort to simplify the usage of [`xbps-src`](https://github.com/void-linux/void-packages),
+there has been a small change to how masterdirs (the containers xbps-src uses
+to build packages) are created and used.
+
+The default masterdir is now called `masterdir-<arch>`, except when `masterdir`
+already exists or when using xbps-src in a container (where it's still `masterdir`).
+
+### Creation
+
+When creating a masterdir for an alternate architecture or libc, the previous
+syntax was:
+
+```
+./xbps-src -m <name> binary-bootstrap <arch>
+```
+
+Now, the `<arch>` should be specified using the new `-A` (host architecture)
+flag:
+
+```
+./xbps-src -A <arch> binary-bootstrap
+```
+
+This will create a new masterdir called `masterdir-<arch>` in the root of your
+void-packages repository checkout.
+
+Arbitrarily-named masterdirs can still be created with `-m <name>`.
+
+### Usage
+
+Instead of specifying the alternative masterdir directly, you can now use the
+`-A` (host architecture) flag to use the `masterdir-<arch>` masterdir:
+
+```
+./xbps-src -A <arch> pkg <pkgname>
+```
+
+Arbitrarily-named masterdirs can still be used with `-m <name>`.