"Can't figure out how to make impfjpeg.cpp. Stop" when compiling ImpGraph lib

[HubertHuckevoll]

Description

When running mkmf / pmake depend followed by compilation, the build process may fail with the following error message:

pmake: Can't figure out how to make impfjpeg.cpp. Stop

Steps to Reproduce

1. Run mkmf followed by pmake depend.
2. Attempt to compile the project.

Root Cause

The generated dependencies.mk file contains incorrect or problematic dependency entries for impfjpeg.cpp, causing the build to fail.

This problem started to occure after the inclusion of the Fjpeg library.

Workaround

Manually edit the dependencies.mk file and remove the following lines:

impfjpeg.obj \
impfjpeg.eobj: impfjpeg.cpp