Fix source/cpp/Makefile separator issues

[codegen-sh]

This PR addresses the remaining issue with the GitHub workflow failing due to missing separators in the source/cpp/Makefile.

The specific error was related to command lines in the Makefile not being properly indented with tabs (Makefiles require tabs, not spaces, for command indentation).

Changes made:

1. Fixed the source/cpp/Makefile by replacing spaces with tabs for command lines

This change should resolve the build issues in the workflow.

---

💻 View my work • About Codegen

[mentatbot]

If you would like me to review this PR, either tag me in a comment or check this box:

• Review PR

_{You can disable automatic comments on my settings page}

[codegen-sh]

I've created this PR to fix the remaining Makefile issues that were causing the workflow to fail. The main problem was in the source/cpp/Makefile where command lines were indented with spaces instead of tabs (Makefiles require tabs for command indentation).

The specific error was:

Makefile:125: *** missing separator (did you mean TAB instead of 8 spaces?). Stop.

This PR fixes the indentation in the source/cpp/Makefile by replacing spaces with tabs for all command lines. This should resolve the build issues in the workflow.

Note that PR #4 already fixed the main Makefile and removed redundant files, but it missed the issues in the source/cpp/Makefile.