This patch is integrated in scikit-image v0.18.0
diff --git a/skimage/restoration/_unwrap_2d.pyx b/skimage/restoration/_unwrap_2d.pyx
index ad0dfa2280..8e2d6ee3ae 100644
--- a/skimage/restoration/_unwrap_2d.pyx
+++ b/skimage/restoration/_unwrap_2d.pyx
@@ -3,13 +3,17 @@
 # cython: nonecheck=False
 # cython: wraparound=False
 
-cdef extern from *:
-    void unwrap2D(double* wrapped_image,
-                  double* unwrapped_image,
-                  unsigned char* input_mask,
-                  int image_width, int image_height,
-                  int wrap_around_x, int wrap_around_y,
-                  char use_seed, unsigned int seed) nogil
+
+cdef extern from "unwrap_2d_ljmu.h":
+    void unwrap2D(
+            double *wrapped_image,
+            double *UnwrappedImage,
+            unsigned char *input_mask,
+            int image_width, int image_height,
+            int wrap_around_x, int wrap_around_y,
+            char use_seed, unsigned int seed
+            ) nogil
+
 
 def unwrap_2d(double[:, ::1] image,
               unsigned char[:, ::1] mask,
diff --git a/skimage/restoration/_unwrap_3d.pyx b/skimage/restoration/_unwrap_3d.pyx
index eac50e70fb..2c9bbfbb1d 100644
--- a/skimage/restoration/_unwrap_3d.pyx
+++ b/skimage/restoration/_unwrap_3d.pyx
@@ -3,13 +3,18 @@
 # cython: nonecheck=False
 # cython: wraparound=False
 
-cdef extern from *:
-  void unwrap3D(double* wrapped_volume,
-                double* unwrapped_volume,
-                unsigned char* input_mask,
-                int image_width, int image_height, int volume_depth,
-                int wrap_around_x, int wrap_around_y, int wrap_around_z,
-                char use_seed, unsigned int seed) nogil
+
+cdef extern from "unwrap_3d_ljmu.h":
+    void unwrap3D(
+            double *wrapped_volume,
+            double *unwrapped_volume,
+            unsigned char *input_mask,
+            int volume_width, int volume_height, int volume_depth,
+            int wrap_around_x, int wrap_around_y, int wrap_around_z,
+            char use_seed, unsigned int seed
+            ) nogil
+
+
 
 def unwrap_3d(double[:, :, ::1] image,
               unsigned char[:, :, ::1] mask,
diff --git a/skimage/restoration/unwrap_2d_ljmu.c b/skimage/restoration/unwrap_2d_ljmu.c
index 690a8d7741..ac60a7d98e 100644
--- a/skimage/restoration/unwrap_2d_ljmu.c
+++ b/skimage/restoration/unwrap_2d_ljmu.c
@@ -39,6 +39,7 @@
 #define NOMASK 0
 #define MASK 1
 
+
 typedef struct {
   double mod;
   int x_connectivity;
diff --git a/skimage/restoration/unwrap_2d_ljmu.h b/skimage/restoration/unwrap_2d_ljmu.h
new file mode 100644
index 0000000000..9b26d808ff
--- /dev/null
+++ b/skimage/restoration/unwrap_2d_ljmu.h
@@ -0,0 +1,9 @@
+void unwrap2D(
+        double *wrapped_image,
+        double *UnwrappedImage,
+        unsigned char *input_mask,
+        int image_width, int image_height,
+        int wrap_around_x, int wrap_around_y,
+        char use_seed, unsigned int seed
+        );
+
diff --git a/skimage/restoration/unwrap_3d_ljmu.c b/skimage/restoration/unwrap_3d_ljmu.c
index fdd9847ae8..301414cb5e 100644
--- a/skimage/restoration/unwrap_3d_ljmu.c
+++ b/skimage/restoration/unwrap_3d_ljmu.c
@@ -40,6 +40,8 @@
 #define NOMASK 0
 #define MASK 1
 
+
+
 typedef struct {
   double mod;
   int x_connectivity;
diff --git a/skimage/restoration/unwrap_3d_ljmu.h b/skimage/restoration/unwrap_3d_ljmu.h
new file mode 100644
index 0000000000..8038639073
--- /dev/null
+++ b/skimage/restoration/unwrap_3d_ljmu.h
@@ -0,0 +1,9 @@
+void unwrap3D(
+        double *wrapped_volume,
+        double *unwrapped_volume,
+        unsigned char *input_mask,
+        int volume_width, int volume_height, int volume_depth,
+        int wrap_around_x, int wrap_around_y, int wrap_around_z,
+        char use_seed, unsigned int seed
+        );
+