diff --git a/lib/mpi/mpi-inline.h b/lib/mpi/mpi-inline.h
index e2b39852b30a..c245ea31f785 100644
--- a/lib/mpi/mpi-inline.h
+++ b/lib/mpi/mpi-inline.h
@@ -30,7 +30,7 @@
 #define G10_MPI_INLINE_H
 
 #ifndef G10_MPI_INLINE_DECL
-#define G10_MPI_INLINE_DECL  extern inline
+#define G10_MPI_INLINE_DECL  static inline
 #endif
 
 G10_MPI_INLINE_DECL mpi_limb_t
diff --git a/lib/mpi/mpi-internal.h b/lib/mpi/mpi-internal.h
index c65dd1bff45a..7eceeddb3fb8 100644
--- a/lib/mpi/mpi-internal.h
+++ b/lib/mpi/mpi-internal.h
@@ -168,19 +168,19 @@ void mpi_rshift_limbs(MPI a, unsigned int count);
 int mpi_lshift_limbs(MPI a, unsigned int count);
 
 /*-- mpihelp-add.c --*/
-mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_size_t s1_size, mpi_limb_t s2_limb);
 mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_ptr_t s2_ptr, mpi_size_t size);
-mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 
 /*-- mpihelp-sub.c --*/
-mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
+static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_size_t s1_size, mpi_limb_t s2_limb);
 mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 			 mpi_ptr_t s2_ptr, mpi_size_t size);
-mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
+static inline mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 		       mpi_ptr_t s2_ptr, mpi_size_t s2_size);
 
 /*-- mpihelp-cmp.c --*/