devenv: Document recent changes

docs/markdown/Commands.md

@@ -345,6 +345,8 @@ These variables are set in environment in addition to those set using [[meson.ad
   schemas is compiled. This is automatically set when using `gnome.compile_schemas()`.
   Note that this requires GLib >= 2.64 when `gnome.compile_schemas()` is used in
   more than one directory.
+- `QEMU_LD_PREFIX` *Since 1.0.0* is set to the `sys_root` value from cross file
+  when cross compiling and that property is defined.
 
 Since *Since 0.62.0* if bash-completion scripts are being installed and the
 shell is bash, they will be automatically sourced.

docs/markdown/snippets/devenv.md

@@ -0,0 +1,15 @@
+## Developer environment improvements
+
+When cross compiling, the developer environment now sets all environment
+variables for the HOST machine. It now also sets `QEMU_LD_PREFIX` to the
+`sys_root` value from cross file if property is defined. That means that cross
+compiled executables can often be run transparently on the build machine, for
+example when cross compiling for aarch64 linux from x86_64 linux.
+
+A new argument `--workdir` has been added, by default it is set to build
+directory. For example, `meson devenv -C builddir --workdir .` can be used to
+remain in the current dir (often source dir) instead.
+
+`--dump` now prints shell commands like `FOO="/prepend/path:$FOO:/append/path"`,
+using the litteral `$FOO` instead of current value of `FOO` from environment.
+This makes easier to evaluate those expressions in a different environment.