a) refer 'perl' in their Makefile, or
b) have a directory name of p5-*, or
c) have any dependency on any p5-* package
Like last time, where this caused no complaints.
ExtUtils::CppGuess attempts to guess the system's C++ compiler that
is compatible with the C compiler that your perl was built with.
It can generate the necessary options to the Module::Build constructor
or to ExtUtils::MakeMaker's WriteMakefile function.