configure: check nc-config and nf-config

[wkliao]

Fix the use of nc-config and nf-config.

TYPE: bug fix

KEYWORDS: nc-config, nf-config

SOURCE: Wei-keng Liao

DESCRIPTION OF CHANGES: Problem: Sometimes $NETCDF/bin/nc-config is used and others nc-config. The same for nf-config. Error messages below appear when the folder of nc-config and nf-config is not in the user's env PATH.

configure: line 163: nc-config: command not found
configure: line 174: nc-config: command not found
expr: syntax error: unexpected argument ‘100’
expr: syntax error: unexpected argument ‘10’
expr: syntax error: missing argument after ‘+’
expr: syntax error: missing argument after ‘+’
configure: line 182: [: -lt: unary operator expected
...
NetCDF version: 
configure: line 917: nc-config: command not found
Enabled NetCDF-4/HDF-5: 
configure: line 918: nc-config: command not found

Solution:

• Use 2 variables nc_config and nf_config
• Requires both NetCDF C and Fortran libraries installed in the same location set in env variable NETCDF.
• Add a check for whether NetCDF is built with parallel I/O enabled by calling nc-config --has-parallel4
• Improve error messages

LIST OF MODIFIED FILES: configure

TESTS CONDUCTED:

• NETCDF env variable is set, but its bin folder does not appear in env PATH