[librsvg] transform.rs: Add missing 'extern'

[Federico Mena Quintero <federico src gnome org>]

commit 12ba8ba37f1e3f5655568889aa3a4e8ad24bd4fc
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Jun 13 08:51:14 2017 -0500

    transform.rs: Add missing 'extern'
    
    How did this work?

 rust/src/transform.rs |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/rust/src/transform.rs b/rust/src/transform.rs
index 753e618..2e31565 100644
--- a/rust/src/transform.rs
+++ b/rust/src/transform.rs
@@ -4,7 +4,6 @@ use ::glib::translate::*;
 use ::glib_sys;
 use ::libc;
 
-
 use std::f64::consts::*;
 
 use parse_transform::*;
@@ -41,7 +40,7 @@ fn make_rotation_matrix (angle_degrees: f64, tx: f64, ty: f64) -> cairo::Matrix
 }
 
 #[no_mangle]
-pub fn rsvg_parse_transform (out_matrix: *mut cairo::Matrix, s: *const libc::c_char) -> glib_sys::gboolean {
+pub extern fn rsvg_parse_transform (out_matrix: *mut cairo::Matrix, s: *const libc::c_char) -> 
glib_sys::gboolean {
     assert! (!out_matrix.is_null ());
     assert! (!s.is_null ());