--- gdal-2.3.1/GNUmakefile.ext_g2clib	2018-06-23 17:05:46.000000000 +0200
+++ gdal-2.3.1/GNUmakefile	2018-07-30 15:56:11.517697753 +0200
@@ -17,6 +17,9 @@
 
 GDAL_OBJ += $(GDAL_ROOT)/ogr/ogrsf_frmts/o/*.o
 
+# Use external grib2c
+LDFLAGS += -lgrib2c
+
 ifeq ($(GNM_ENABLED),yes)
    GDAL_OBJ += $(GDAL_ROOT)/gnm/*.o $(GDAL_ROOT)/gnm/gnm_frmts/o/*.o
 endif
--- gdal-2.3.1/frmts/grib/GNUmakefile.ext_g2clib	2018-06-23 17:05:47.000000000 +0200
+++ gdal-2.3.1/frmts/grib/GNUmakefile	2018-07-30 17:21:54.693877257 +0200
@@ -7,7 +7,9 @@
 OBJ	=	gribdataset.o gribcreatecopy.o \
                 clock.o \
                 degrib1.o \
-                degrib2.o inventory.o metaname.o myerror.o filedatasource.o memorydatasource.o grib1tab.o myutil.o metaparse.o weather.o metaprint.o grib2api.o myassert.o scan.o tendian.o gridtemplates.o drstemplates.o pdstemplates.o gbits.o g2_free.o g2_unpack1.o g2_unpack2.o g2_unpack3.o g2_unpack4.o g2_unpack5.o g2_unpack6.o g2_unpack7.o g2_info.o g2_getfld.o simunpack.o comunpack.o pack_gp.o reduce.o specunpack.o rdieee.o mkieee.o int_power.o simpack.o compack.o cmplxpack.o misspack.o \
+                degrib2.o inventory.o metaname.o myerror.o filedatasource.o memorydatasource.o grib1tab.o myutil.o metaparse.o weather.o metaprint.o grib2api.o myassert.o scan.o tendian.o hazard.o
+##in grid2c
+#gridtemplates.o drstemplates.o pdstemplates.o gbits.o g2_free.o g2_unpack1.o g2_unpack2.o g2_unpack3.o g2_unpack4.o g2_unpack5.o g2_unpack6.o g2_unpack7.o g2_info.o g2_getfld.o simunpack.o comunpack.o pack_gp.o reduce.o specunpack.o rdieee.o mkieee.o int_power.o simpack.o compack.o cmplxpack.o misspack.o \
 		dec_jpeg2000.o jpcunpack.o hazard.o
 
 ifeq ($(PNG_SETTING),internal)
@@ -20,7 +22,8 @@
 
 ifeq ($(PNG_SETTING),external)
 EXTRAFLAGS      :=      $(EXTRAFLAGS) -DUSE_PNG
-OBJ     :=      $(OBJ) pngunpack.o dec_png.o
+## in grib2c
+## OBJ     :=      $(OBJ) pngunpack.o dec_png.o
 endif
 
 CPPFLAGS	:=	 $(CPPFLAGS) $(EXTRAFLAGS)
--- gdal-2.3.1/frmts/grib/degrib/degrib/engribapi.c~	2018-06-23 17:06:56.000000000 +0200
+++ gdal-2.3.1/frmts/grib/degrib/degrib/engribapi.c	2018-07-30 16:06:32.166815369 +0200
@@ -19,9 +19,9 @@
 #include "grib2api.h"
 #include "engribapi.h"
 #include "myassert.h"
-#include "gridtemplates.h"
-#include "pdstemplates.h"
-#include "drstemplates.h"
+#include <gridtemplates.h>
+#include <pdstemplates.h>
+#include <drstemplates.h>
 
 #ifdef MEMWATCH
 #include "memwatch.h"
@@ -428,7 +428,7 @@
               double meshLat, double orientLon, double scaleLat1,
               double scaleLat2, double southLat, double southLon)
 {
-   const struct gridtemplate *templatesgrid = get_templatesgrid();
+
    int i;               /* loop counter over number of GDS templates. */
    double unit;         /* Used to convert from stored value to degrees
                          * lat/lon. See GRIB2 Regulation 92.1.6 */
@@ -649,7 +649,7 @@
                 double dSurfVal2)
 {
    int i;               /* loop counter over number of PDS templates. */
-   const struct pdstemplate *templatespds = get_templatespds();
+
 
    /* analysis template (0) */
    /* In addition templates (1, 2, 5, 8, 9, 12) begin with 4.0 info. */
@@ -1205,7 +1205,7 @@
               uChar orderOfDiff)
 {
    int i;               /* loop counter over number of DRS templates. */
-   const struct drstemplate *templatesdrs = get_templatesdrs();
+
 
    /* Find NCEP's template match */
    for (i = 0; i < MAXDRSTEMP; i++) {
--- gdal-2.3.1/frmts/grib/degrib/degrib/grib2api.c~	2018-06-23 17:06:56.000000000 +0200
+++ gdal-2.3.1/frmts/grib/degrib/degrib/grib2api.c	2018-07-30 16:09:19.161190928 +0200
@@ -18,13 +18,13 @@
 #include <stdlib.h>
 #include <string.h>
 #include "grib2api.h"
-#include "grib2.h"
+#include <grib2.h>
 #include "scan.h"
 #include "tendian.h"
 #include "myassert.h"
-#include "gridtemplates.h"
-#include "pdstemplates.h"
-#include "drstemplates.h"
+#include <gridtemplates.h>
+#include <pdstemplates.h>
+#include <drstemplates.h>
 
 #include "cpl_port.h"
 
@@ -818,7 +818,7 @@
    char f_ignoreScan;   /* Flag to ignore the attempt at changing the scan */
    sInt4 dummyScan;     /* Dummy place holder for call to Transfer routines
                          * if ignoring scan. */
-   const struct gridtemplate *templatesgrid = get_templatesgrid();
+
 
    myAssert(*ndjer >= 8);
    /* Init the error handling array. */
@@ -1094,7 +1094,7 @@
    {
    curIndex = 9;
    for (i = 0; i < gfld->ipdtlen; i++) {
-      const struct pdstemplate *templatespds = get_templatespds();
+
       if( curIndex >= *ns4 )
       {
           /* Should we error out instead ? */
@@ -1126,7 +1126,7 @@
    }
    curIndex = 11;
    for (i = 0; i < gfld->idrtlen; i++) {
-      const struct drstemplate *templatesdrs = get_templatesdrs();
+
       is5[curIndex] = gfld->idrtmpl[i];
       curIndex += abs(templatesdrs[drsIndex].mapdrs[i]);
    }
--- gdal-2.3.1/frmts/grib/gribcreatecopy.cpp.orig	2018-07-30 17:11:49.764512589 +0200
+++ gdal-2.3.1/frmts/grib/gribcreatecopy.cpp	2018-07-30 17:12:09.413850306 +0200
@@ -38,7 +38,7 @@
 
 #include "degrib/degrib/meta.h"
 CPL_C_START
-#include "degrib/g2clib/grib2.h"
+#include <grib2.h>
 CPL_C_END
 
 /************************************************************************/
--- gdal-2.3.1/frmts/grib/gribdataset.cpp.orig	2018-07-30 17:00:11.418053168 +0200
+++ gdal-2.3.1/frmts/grib/gribdataset.cpp	2018-07-30 17:09:04.360087637 +0200
@@ -61,8 +61,10 @@
 #include "degrib/degrib/myerror.h"
 #include "degrib/degrib/type.h"
 CPL_C_START
-#include "degrib/g2clib/grib2.h"
-#include "degrib/g2clib/pdstemplates.h"
+#include <grib2.h>
+#include <pdstemplates.h>
+#include <gridtemplates.h>
+#include <drstemplates.h>
 CPL_C_END
 #include "gdal.h"
 #include "gdal_frmts.h"