[TOSQUASH] Use prefix flag support from optparse

Author: devajithvs

core/dictgen/src/rootcling_impl.cxx

@@ -3811,21 +3811,21 @@ void DefineRootclingOptions(ROOT::RCmdLineOpts &opts)
    opts.AddFlag({"--lib-list-prefix"}, FT::kWithArg, "An ACLiC feature which exports the list of dependent libraries.");
    opts.AddFlag({"-rmf"}, FT::kWithArg, "Generate a rootmap file with the specified name.");
    opts.AddFlag({"-s"}, FT::kWithArg, "The path to the library of the built dictionary.");
-   opts.AddFlag({"-isysroot"}, FT::kWithArg, "Specify an isysroot.");
+   opts.AddFlag({"-isysroot"}, FT::kWithArg, "Specify an isysroot.", FO::kFlagPrefixArg);
 
    // flags with repeated args
    opts.AddFlag({"-rml"}, FT::kWithArg, "Generate rootmap file.", FO::kFlagAllowMultiple);
    opts.AddFlag({"-moduleMapFile"}, FT::kWithArg, "Specify a C++ modulemap file.", FO::kFlagAllowMultiple);
    opts.AddFlag({"-m"}, FT::kWithArg, "The list of dependent modules of the dictionary.", FO::kFlagAllowMultiple);
    opts.AddFlag({"-excludePath"}, FT::kWithArg, "Do not store the <path> in the dictionary.", FO::kFlagAllowMultiple);
    opts.AddFlag({"-isystem"}, FT::kWithArg, "Specify a system include path.", FO::kFlagAllowMultiple);
-   opts.AddFlag({"-I"}, FT::kWithArg, "Specify an include path.", FO::kFlagAllowMultiple);
+   opts.AddFlag({"-I"}, FT::kWithArg, "Specify an include path.", FO::kFlagAllowMultiple | FO::kFlagPrefixArg);
    opts.AddFlag({"--compilerI"}, FT::kWithArg,
                 "Specify a compiler default include path, to suppress unneeded `-isystem` arguments.",
-                FO::kFlagAllowMultiple);
-   opts.AddFlag({"-D"}, FT::kWithArg, "Specify defined macros.", FO::kFlagAllowMultiple);
-   opts.AddFlag({"-U"}, FT::kWithArg, "Specify undefined macros.", FO::kFlagAllowMultiple);
-   opts.AddFlag({"-W"}, FT::kWithArg, "Specify compiler diagnostics options.", FO::kFlagAllowMultiple);
+                FO::kFlagAllowMultiple | FO::kFlagPrefixArg);
+   opts.AddFlag({"-D"}, FT::kWithArg, "Specify defined macros.", FO::kFlagAllowMultiple | FO::kFlagPrefixArg);
+   opts.AddFlag({"-U"}, FT::kWithArg, "Specify undefined macros.", FO::kFlagAllowMultiple | FO::kFlagPrefixArg);
+   opts.AddFlag({"-W"}, FT::kWithArg, "Specify compiler diagnostics options.", FO::kFlagAllowMultiple | FO::kFlagPrefixArg);
    opts.AddFlag({"-mByproduct"}, FT::kWithArg,
                 "The list of the expected implicit modules build as part of building the current module.",
                 FO::kFlagAllowMultiple);