r_cc: Return the default R-configured C compiler (possibly with flags)
Description
This function queries common places to find the C compiler used by R.
It checks Sys.getenv("CC"), then R CMD config CC, and finally cc on PATH.
The returned value may include flags (e.g., 'gcc -std=...').
Usage
r_cc()
Arguments
Value
Character scalar with compiler program (or empty string).