A weak aspect of mbeddr has always been the interoperability with existing textual C source. We have made many attempts at parsing C sources and importing them into mbeddr, all with different degrees of success and various different problems.
Out latest, and so far most successful attempt is based on TypeChef by Christian Kästner and friends). Check out this video to get an impression of the current capabilities..
We are still working on importing whole header files (as external modules) and C files. We also have a good handle on the preprocessor (defines, macros, ifdefs), because TypeChef deals with them gracefully.