make "appears nonfunctional" message more helpful

Author: mohawk2

lib/PDL/Graphics/Simple/Gnuplot.pm

@@ -124,7 +124,7 @@ sub new {
     # Force a recheck on failure, in case the user fixed gnuplot.
     # Also loads PDL::Graphics::Gnuplot.
     unless(check()) {
-	die "$mod->{shortname} appears nonfunctional\n" unless(check(1));
+	die "$mod->{shortname} appears nonfunctional: $mod->{msg}\n" unless(check(1));
     }
 
     # Generate the @params array to feed to gnuplot

lib/PDL/Graphics/Simple/PGPLOT.pm

@@ -104,7 +104,7 @@ sub new {
     # Force a recheck on failure, in case the user fixed PGPLOT.
     # Also loads PDL::Graphics::PGPLOT::Window.
     unless(check()) {
-	die "$mod->{shortname} appears nonfunctional\n" unless(check(1));
+	die "$mod->{shortname} appears nonfunctional: $mod->{msg}\n" unless(check(1));
     }
 
     # Figure the device name and size to feed to PGPLOT.

lib/PDL/Graphics/Simple/PLplot.pm

@@ -176,7 +176,7 @@ sub new {
 
     # Force a recheck on failure, in case the user fixed PLplot.
     unless(check()) {
-	die "$mod->{shortname} appears nonfunctional\n" unless(check(1));
+	die "$mod->{shortname} appears nonfunctional: $mod->{msg}\n" unless(check(1));
     }
 
     # Figure the device name and size to feed to PLplot.

lib/PDL/Graphics/Simple/Prima.pm

@@ -126,7 +126,7 @@ sub new {
 
 
     unless( check() ) {
-	die "$mod->{shortname} appears nonfunctional\n" unless(check(1));
+	die "$mod->{shortname} appears nonfunctional: $mod->{msg}\n" unless(check(1));
     }
 
     my $size = PDL::Graphics::Simple::_regularize_size($opt->{size},'px');