diff --git a/Makefile b/Makefile
index 05d4c77b..9919659f 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,6 @@ CC ?= mpicc
 CFLAGS ?= -Wall -Wextra -Wpedantic -Wno-unused-function -Wno-unused-parameter -std=c99 -g
 LDFLAGS ?=
 DEBUG ?= 0
-MPI ?= 1
 UNDERSCORE ?= 1
 SYNC_BY_REDUCTION ?= 1
 BLAS ?= 0
@@ -40,9 +39,7 @@ else
   CFLAGS += -O2
 endif
 
-ifneq ($(MPI),0)
-  PP += -DMPI
-endif
+PP += -DPARRSB_MPI
 
 ifneq ($(UNDERSCORE),0)
   PP += -DPARRSB_UNDERSCORE
diff --git a/src/parRSB.h b/src/parRSB.h
index 2ca8977e..67ce68c9 100644
--- a/src/parRSB.h
+++ b/src/parRSB.h
@@ -3,11 +3,11 @@
 
 #include "gslib.h"
 
-#if !defined(MPI)
+#if !defined(GSLIB_USE_MPI)
 #error "gslib needs to be compiled with MPI"
 #endif
 
-#if !defined(GLOBAL_LONG_LONG)
+#if !defined(GSLIB_USE_GLOBAL_LONG_LONG)
 #error "gslib needs to be compiled with GLOBAL_LONG_LONG"
 #endif
 
@@ -64,7 +64,7 @@ int parrsb_conn_mesh(long long *vtx, double *coord, uint nel, unsigned nDim,
                      MPI_Comm comm);
 
 #define fparrsb_conn_mesh                                                      \
-  FORTRAN_UNPREFIXED(fparrsb_conn_mesh, FPARRSB_CONN_MESH)
+  GS_FORTRAN_UNPREFIXED(fparrsb_conn_mesh, FPARRSB_CONN_MESH)
 void fparrsb_conn_mesh(long long *vtx, double *coord, int *nel, int *nDim,
                        long long *periodicInfo, int *nPeriodicFaces,
                        double *tol, MPI_Fint *fcomm, int *err);
diff --git a/src/parrsb.c b/src/parrsb.c
index 7fc68780..dc7fa0db 100644
--- a/src/parrsb.c
+++ b/src/parrsb.c
@@ -184,7 +184,7 @@ static void restore_original(int *part, struct crystal *cr, struct array *elist,
 }
 
 static void initialize_node_aux(struct comm *c, const struct comm *const gc) {
-#ifdef MPI
+#ifdef PARRSB_MPI
   MPI_Comm node;
   MPI_Comm_split_type(gc->c, MPI_COMM_TYPE_SHARED, gc->id, MPI_INFO_NULL,
                       &node);