Fix misleading description of configure options.

* We have neither --with-eccodes-root nor --with-grib_api-root.

configure

@@ -1689,13 +1689,11 @@ Optional Packages:
   --with-netcdf=<yes|no|directory> (default=no)
                           location of NetCDF library (lib and include subdirs)
   --with-eccodes=<yes|no|directory>
-                          library for grib2 encoding/decoding; if a directory
-                          is given, it will be used as a value for
-                          --with-eccodes-root
+                          location of ECCODES library for grib2
+                          encoding/decoding (lib and include subdirs)
   --with-grib_api=<yes|no|directory>
-                          library for grib2 encoding/decoding; if a directory
-                          is given, it will be used as a value for
-                          --with-grib_api-root
+                          location of GRIB_API library for grib2
+                          encoding/decoding (lib and include subdirs)
   --with-mpi-root         set directory to search for MPI headers and library
   --with-mpi-include      specifically set directory to search for MPI
                           headers, [default=$with_mpi_root/include]

m4/acx_options.m4

@@ -168,7 +168,7 @@ ECCODES_INCLUDE=''
 ECCODES_LIBS=''
 AC_ARG_WITH([eccodes],
             [AS_HELP_STRING([--with-eccodes=<yes|no|directory>],
-                            [library for grib2 encoding/decoding; if a directory is given, it will be used as a value for --with-eccodes-root])],
+                            [location of ECCODES library for grib2 encoding/decoding (lib and include subdirs)])],
             [AS_CASE(["$with_eccodes"],
                      [no],[AC_MSG_CHECKING([for ECCODES library])
                            AC_MSG_RESULT([suppressed])],
@@ -204,7 +204,7 @@ GRIB_API_INCLUDE=''
 GRIB_API_LIBS=''
 AC_ARG_WITH([grib_api],
             [AS_HELP_STRING([--with-grib_api=<yes|no|directory>],
-                            [library for grib2 encoding/decoding; if a directory is given, it will be used as a value for --with-grib_api-root])],
+                            [location of GRIB_API library for grib2 encoding/decoding (lib and include subdirs)])],
             [AS_CASE(["$with_grib_api"],
                      [no],[AC_MSG_CHECKING([for GRIB_API library])
                            AC_MSG_RESULT([suppressed])],