ChIPKernels fails to compile in R 4.5 because of change in names of R API macros

[afayyazuddin]

The error is in compilation of hamming.c due to removal of the macros Calloc, Free, and Realloc from the R API (https://stat.ethz.ch/R-manual/R-devel/doc/manual/R-exts.html). The new macros are now called R_Calloc, R_Free, and R_Realloc and the code compiles when the old names are replaced with the new ones.
A screenshot of the compilation error is shown below: