pkg-config-wrapper: Init

This fixes longstanding build issues

pkgs/build-support/pkg-config-wrapper/pkg-config-wrapper.sh

@@ -0,0 +1,21 @@
+#! @shell@
+set -eu -o pipefail +o posix
+shopt -s nullglob
+
+if (( "${NIX_DEBUG:-0}" >= 7 )); then
+    set -x
+fi
+
+source @out@/nix-support/utils.bash
+
+if [ -z "${NIX_PKG_CONFIG_WRAPPER_FLAGS_SET_@suffixSalt@:-}" ]; then
+    source @out@/nix-support/add-flags.sh
+fi
+
+if (( ${#role_suffixes[@]} > 0 )); then
+	# replace env var with nix-modified one
+    PKG_CONFIG_PATH=$PKG_CONFIG_PATH_@suffixSalt@ exec @prog@ "$@"
+else
+	# pkg-config isn't a bonafied dependency so ignore setup hook entirely
+	exec @prog@ "$@"
+fi