yaml: move to subdirectory

A pending sdbusplus change (I38b69bc67b6a3d80cda1b508a76e106a50d8ab93)
is going to require YAML to be in a specific subdirectory and not in
the root.  Move here in prep for that change.

Also add in the regenerate-meson script as a helper to regenerate
the sdbusplus meson files for this repository.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I2c9e74b85550e3e8f0f5cb56a82e85c5b13c6d00
diff --git a/gen/regenerate-meson b/gen/regenerate-meson
new file mode 100755
index 0000000..a39ad64
--- /dev/null
+++ b/gen/regenerate-meson
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+REPO_ROOT=$(git rev-parse --show-toplevel)
+
+# Find sdbus++-gen-meson
+#   1. Check $SDBUSPP_GEN_MESON
+#   2. Check in $PATH
+#   3. Check in subprojects/sdbusplus
+if [ ! -x "$SDBUSPP_GEN_MESON" ]; then
+    SDBUSPP_GEN_MESON="$(which sdbus++-gen-meson 2> /dev/null)"
+fi
+if [ ! -x "$SDBUSPP_GEN_MESON" ]; then
+    SDBUSPP_GEN_MESON="$REPO_ROOT/subprojects/sdbusplus/tools/sdbus++-gen-meson"
+fi
+if [ ! -x "$SDBUSPP_GEN_MESON" ]; then
+    echo "Cannot find sdbus++-gen-meson ($SDBUSPP_GEN_MESON)."
+    exit 1
+fi
+
+$SDBUSPP_GEN_MESON \
+    --command meson \
+    --directory "$REPO_ROOT/yaml" \
+    --output "$REPO_ROOT/gen"