diff --git a/Dockerfile b/Dockerfile
index 553cc57f..af564005 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,6 +20,8 @@ ADD doc /app/doc
 ADD tutorials /app/doc
 ADD MANIFEST.in LICENSE LICENSE.txt .gitmodules .gitignore setup.py /app/
 
+# add compiler
+RUN apt-get update && apt-get install -y build-essential
 # compile/setup pytom
 RUN python setup.py install --prefix $CONDA_PREFIX
 
diff --git a/pytom/pytomc/sh_alignment/SpharmonicKit27/test_stability_naive.c b/pytom/pytomc/sh_alignment/SpharmonicKit27/test_stability_naive.c
index 3321095d..bd2d41db 100644
--- a/pytom/pytomc/sh_alignment/SpharmonicKit27/test_stability_naive.c
+++ b/pytom/pytomc/sh_alignment/SpharmonicKit27/test_stability_naive.c
@@ -61,6 +61,7 @@
 
 #include <math.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "naive_synthesis.h"
 
diff --git a/pytom/pytomc/sh_alignment/frm/src/lib_eul.c b/pytom/pytomc/sh_alignment/frm/src/lib_eul.c
index 986736fe..9ee498ff 100644
--- a/pytom/pytomc/sh_alignment/frm/src/lib_eul.c
+++ b/pytom/pytomc/sh_alignment/frm/src/lib_eul.c
@@ -379,8 +379,8 @@ void eu_lattman (double eu_range[3][2], double delta, unsigned long *eu_count, f
   double sparsing_cosine = cos(0.5*delta*ROT_CONV); 
   /* suggested Lattman sparsing tolerance: 0.5 delta */
 
-  double deviation_cosine();
-  void get_rot_matrix();
+  double deviation_cosine(double [3][3], double [3][3);
+  void get_rot_matrix(double [3][3], double, double, double);
 
   psi_steps   = (int)ceil((eu_range[0][1]-eu_range[0][0])/delta);
   theta_steps = (int)ceil((eu_range[1][1]-eu_range[1][0])/delta);
@@ -485,8 +485,8 @@ char similar_eulers(double a1,double a2,double a3,double b1,double b2,double b3)
 /* checks if two orientations are within 1 degree                          */
 /* this can be slow if one of the orientations remains the same in a loop  */
 
-  void get_rot_matrix ();
-  double deviation_cosine ();
+  void get_rot_matrix (double [3][3], double, double, double);
+  double deviation_cosine (double [3][3], double [3][3);
   
   double matrix1[3][3],matrix2[3][3];
   
diff --git a/pytom/pytomc/sh_alignment/frm/swig/frm.c b/pytom/pytomc/sh_alignment/frm/swig/frm.c
index 4b63eef3..106a21a8 100644
--- a/pytom/pytomc/sh_alignment/frm/swig/frm.c
+++ b/pytom/pytomc/sh_alignment/frm/swig/frm.c
@@ -723,7 +723,7 @@ static double distance_eulers(unsigned long i, unsigned long j, double *corr[]){
   /* returns the distance between the rotations given by the Euler angles in
      corr[1,2,3][i] and corr[1,2,3][j] */
 
-  extern void get_rot_matrix ();
+  extern void get_rot_matrix (double [3][3], double, double, double);
   double matrix1[3][3],matrix2[3][3]; 
   int k, l;
   double temp, trace;
@@ -748,7 +748,7 @@ static double distance_eulers(unsigned long i, unsigned long j, double *corr[]){
 double angle_distance(double a1, double a2, double a3, double b1, double b2, double b3)
 /* psi, the, phi order */
 {
-  extern void get_rot_matrix ();
+  extern void get_rot_matrix (double [3][3], double, double, double);
   double matrix1[3][3],matrix2[3][3]; 
   int k, l;
   double temp, trace;