common/hooks/pre-pkg/06-verify-python-deps: add hook

compares rdeps and Python module metadata to find missing dependencies
for python packages. this uses virtual packages to map python canonical
package names to void packages.

common/hooks/pre-pkg/06-verify-python-deps.sh

@@ -0,0 +1,22 @@
+# vim: set ts=4 sw=4 et:
+#
+# This hook executes the following tasks:
+#	- Verifies python module dependencies from dist-info's METADATA and egg-info's PKG-INFO
+
+py3_cmd() {
+    env PYTHONPATH="${XBPS_MASTERDIR}/${py3_sitelib}-bootstrap" "${py3_bin}" "$@"
+}
+
+hook() {
+    local py3_bin="${XBPS_MASTERDIR}/usr/bin/python3"
+    local -a _pydeps=()
+
+    if [ -z "$nopyprovides" ] && [ -d "${PKGDESTDIR}/${py3_sitelib}" ] && \
+       [ -x "${py3_bin}" ] && py3_cmd -c "import packaging"; then
+            py3_cmd "${XBPS_COMMONDIR}"/scripts/parse-py-metadata.py \
+                -S "${PKGDESTDIR}/${py3_sitelib}" -v "${pkgver}" depends \
+                ${NOCOLORS:+-C} ${XBPS_STRICT:+-s} -e "${python_extras}" \
+                -V <( $XBPS_QUERY_XCMD -R -p provides -s "py3:" ) -D "${PKGDESTDIR}/rdeps" \
+                || msg_error "$pkgver: failed to verify python module dependencies\n"
+    fi
+}