Allow multiple -D options

build.sbt

@@ -1,6 +1,6 @@
 name := "millfork"
 
-version := "0.3.30"
+version := "0.3.31-SNAPSHOT"
 
 // keep it at 2.12.11 for GraalVM native image compatibility!
 scalaVersion := "2.12.11"

src/main/scala/millfork/Main.scala

@@ -499,7 +499,7 @@ object Main {
       } else {
         errorReporting.fatal("Invalid syntax for -D option")
       }
-    }.description("Define a feature value for the preprocessor.")
+    }.description("Define a feature value for the preprocessor.").maxCount(Integer.MAX_VALUE)
 
     boolean("-finput_intel_syntax", "-finput_zilog_syntax").repeatable().action((c,v) =>
       c.changeFlag(CompilationFlag.UseIntelSyntaxForInput, v)