Patch mummerplot to work with gnuplot 5 (#9000)

* Skip 'set mouse clipboardformat' on gnuplot 5

Based on changes in mummerplot v4 to cope with being
run on gnuplot 5, with a tweak to still work on older
versions of gnuplot. See also:

mummer4/mummer#64

* fix linting

* Include directory name in patch path

* Try including the tar-ball directory name too

* Was missing .pl in the filename

* Debugging: Stop hiding test comand output

* Declare run-time libstdc++ dependency

* Revert "Debugging: Stop hiding test comand output"

This reverts commit 622d827.

recipes/mummer/meta.yaml

@@ -3,7 +3,7 @@ about:
     license: "The Artistic License"
     summary: "MUMmer is a system for rapidly aligning entire genomes"
 build:
-  number: 4
+  number: 5
   skip: False
 package:
   name: mummer
@@ -12,11 +12,14 @@ source:
   fn: MUMmer3.23.tar.gz
   sha256: 1efad4f7d8cee0d8eaebb320a2d63745bb3a160bb513a15ef7af46f330af662f
   url: https://downloads.sourceforge.net/project/mummer/mummer/3.23/MUMmer3.23.tar.gz
+  patches:
+    - patches/gnuplot_mouse_clipboardformat.patch
 requirements:
   build:
-    - perl-threaded # [not osx]
+    - perl # [not osx]
   run:
-    - perl-threaded # [not osx]
+    - perl # [not osx]
+    - libstdcxx-ng # [linux]
 test:
     commands:
         - "mummer -h &> /dev/null"

recipes/mummer/patches/gnuplot_mouse_clipboardformat.patch

@@ -0,0 +1,11 @@
+--- MUMmer3.23/scripts/mummerplot.pl	2018-05-22 17:01:01.000000000 +0100
++++ MUMmer3.23/scripts/mummerplot.pl.new	2018-05-22 17:01:52.000000000 +0100
+@@ -1151,7 +1151,7 @@
+         $P_KEY = "unset key";
+         $P_FORMAT .= "\nset mouse format \"$TFORMAT\"";
+         $P_FORMAT .= "\nset mouse mouseformat \"$MFORMAT\"";
+-        $P_FORMAT .= "\nset mouse clipboardformat \"$MFORMAT\"";
++        $P_FORMAT .= "\nif(GPVAL_VERSION < 5) set mouse clipboardformat \"$MFORMAT\"";
+     }
+     else {
+         $P_LS = "set linestyle";