diff -Nrup a/python3/c/constraints.c b/python3/c/constraints.c
--- a/python3/c/constraints.c	2019-08-08 01:13:47.000000000 -0600
+++ b/python3/c/constraints.c	2019-10-15 14:53:25.321013840 -0600
@@ -56,7 +56,7 @@ INLINE void vec9_diffs(double* target_xv
    target_xv[8] = R_iv[2*3 + 2] - R_iv[0*3 + 2]; // dH1H2_z
 }
 
-INLINE void vec9_massdiffs(double* target_xv, double* im_i, double* P_iv)
+static INLINE void vec9_massdiffs(double* target_xv, double* im_i, double* P_iv)
 {
    // R1-R2
    target_xv[0] = im_i[0] * P_iv[0*3 + 0] - im_i[1] * P_iv[1*3 + 0]; // dOH1_x
@@ -179,7 +179,7 @@ INLINE double LJ(double A, double B, dou
   return A / r12 + B/r6;
 }
 
-INLINE double pair_interaction_cutoff(double A, double B, double cutoff, double width, double* Z_i, double* Ra_iv, double* Rb_iv, double* Fa_iv, double* Fb_iv, unsigned char* pbc, double* celldiag)
+static INLINE double pair_interaction_cutoff(double A, double B, double cutoff, double width, double* Z_i, double* Ra_iv, double* Rb_iv, double* Fa_iv, double* Fb_iv, unsigned char* pbc, double* celldiag)
 {
   double d_v[3];
   vec3_submin(d_v, Ra_iv + 0*3, Rb_iv + 0*3, pbc, celldiag);