Turning on PIO Support within ESMF

[danrosen25]

In order to support the default build for ESMF and support PIO dependent ESMF features we can add -lpioc to the linker flags using the below changes to Config.pl. A more robust solution would include scanning the esmf.mk to see if PIO was enabled within ESMF. There's an example of reading the esmf.mk for use_esmf_trace.

Here's the simplest solution, which works because the default build for ESMF installs lpioc into the LIB_ESMF directory.

print "Use PIO? (1-yes, 0-no, default=0): ";
$use_pio=<stdin>;
chomp($use_pio);
if($use_pio eq ""){
   $use_pio = 0;
}

or we can use an environment variable that doesn't prompt the user

# USE_PIO does not prompt user
if ($ENV{USE_PIO} eq '1') {
   $use_pio = 1;
}

if($use_pio == 1){
   $ldflags = $ldflags." -lpioc";
}