[librsvg/rustification] marker.rs: Use cairo_sys::cairo_path_t correctly

[Federico Mena Quintero <federico src gnome org>]

commit 078a6ad19a1ecb862f20fd1bdd7f4458cfd649ab
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Nov 1 17:03:05 2016 -0600

    marker.rs: Use cairo_sys::cairo_path_t correctly
    
    I was requesting the cairo-rs crate somewhat incorrectly in Cargo.toml,
    and not requesting cairo-sys-rs at all.  Thus, I thought I needed to
    patch cairo-rs to let me access a cairo_path_t.  It turns out it's
    already available; one just has to declare the crate correctly...

 rust/Cargo.toml    |    7 ++++++-
 rust/src/marker.rs |    7 +++++--
 2 files changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index dcbb3a1..d671baa 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -5,7 +5,12 @@ authors = ["Federico Mena Quintero <federico gnome org>"]
 
 [dependencies]
 libc = "0.2"
-cairo-rs = { git = "https://github.com/federicomenaquintero/cairo.git"; }
+
+[dependencies.cairo-sys-rs]
+git = "https://github.com/gtk-rs/cairo.git";
+
+[dependencies.cairo-rs]
+git = "https://github.com/gtk-rs/cairo.git";
 
 [lib]
 name = "rsvg_internals"
diff --git a/rust/src/marker.rs b/rust/src/marker.rs
index 5004e10..658d68c 100644
--- a/rust/src/marker.rs
+++ b/rust/src/marker.rs
@@ -1,5 +1,6 @@
 extern crate libc;
 extern crate cairo;
+extern crate cairo_sys;
 
 #[derive(Debug, PartialEq)]
 pub enum Segment {
@@ -292,7 +293,7 @@ pub enum RsvgDrawingCtx {}
 pub enum RsvgPathBuilder {}
 
 extern "C" {
-    fn rsvg_path_builder_copy_path (builder: *mut RsvgPathBuilder) -> *mut cairo::cairo_path_t;
+    fn rsvg_path_builder_copy_path (builder: *mut RsvgPathBuilder) -> *mut cairo_sys::cairo_path_t;
     fn rsvg_marker_render (marker_name: *const libc::c_char,
                            xpos: f64,
                            ypos: f64,
@@ -367,11 +368,13 @@ pub extern fn rsvg_rust_render_markers (ctx: *mut RsvgDrawingCtx,
         return;
     }
 
-    let cairopath: *mut cairo::cairo_path_t;
+    let cairopath: *mut cairo_sys::cairo_path_t;
 
     unsafe { cairopath = rsvg_path_builder_copy_path (builder); }
     let path = cairo::Path::wrap (cairopath);
 
+    /* FIXME: free the path with rsvg_cairo_path_destroy() */
+
     /* Convert the path to a list of segments and bare points */
     let segments = path_to_segments (path);