Complete the cpp and makefile file type

[yantaozhao]

No description provided.

[petdance]

The uppercase H and C are unnecessary because extension checking is case-insensitive.

I'm not sure it makes sense to exclude Makefile.am. It's not really a Makefile.

[yantaozhao]

1. Technically speaking, it's not right to treat the cplusplus file extension case-insensitive, since the uppercase .C is indeed the cplusplus source code file, but not c file. Please see https://gcc.gnu.org/onlinedocs/gcc/Overall-Options.html
2. For makefile, at least the Makefile/makefile/GNUMakefile and *.mk should be added. Meanwhile, I think it's more convenient to add the Makefile.am as the makefile file. See https://www.gnu.org/software/automake/manual/html_node/amhello_0027s-Makefile_002eam-Setup-Explained.html

BRs.
😺