--- fastqc.orig	2023-05-26 08:02:49.123718275 +0100
+++ fastqc	2023-05-26 08:12:19.980320240 +0100
@@ -38,13 +38,21 @@
 	$delimiter = ';';
 }
 
-if ($ENV{CLASSPATH}) {
-	$ENV{CLASSPATH} .= "$delimiter$RealBin$delimiter$RealBin/htsjdk.jar$delimiter$RealBin/jbzip2-0.9.jar$delimiter$RealBin/cisd-jhdf5.jar";
-}
-else {
-	$ENV{CLASSPATH} = "$RealBin$delimiter$RealBin/htsjdk.jar$delimiter$RealBin/jbzip2-0.9.jar$delimiter$RealBin/cisd-jhdf5.jar";
-}
-
+# The lib dir is $RealBin/../lib
+# start with list of jars we need and prefix them with the lib dir
+# then stick CLASSPATH onto the front (empty or otherwise...)
+# then filter out anything that's empty (perhaps CLASSPATH...)
+# then join all the remainings bits with the delimiter.
+use File::Basename;
+use File::Spec::Functions;
+my $_lib = catfile(dirname($RealBin), 'lib');
+$ENV{CLASSPATH} =
+    join($delimiter,
+         grep {$_}
+             ($ENV{CLASSPATH},
+              $_lib,
+              map {"$_lib/$_"}
+                  qw(htsjdk.jar jbzip2-0.9.jar cisd-jhdf5.jar)));
 
 # We need to find the java interpreter.  We'll start from the assumption that this
 # is included in the path.