@jakobschauer Here is m-pd.h from pd 0.54.1 .... m_pd.h .... I haven't compared it to older versions so if you are trying to build for another version of Pd please ask.
Here are all the files from the source folder of that version...... Pd source 0.54.1.zip
I hope that helps but I have no idea how to compile correctly. They are from a windows version but I think .h files are the same.
If not then download Pd without installing it and go to the /src folder to find them.
David.