FORCE_CC, CC, CFLAGS and LFLAGS are non-standard

The Makefiles use FORCE_CC and CC to refer to the chose C++ compiler. By convention CC is used for C compiler, and CXX is the C++ compiler. It would avoid user confusion to renames as FORCE_CXX and CXX throughout.

Similarly the compile time flags should be in CXXFLAGS, not CFLAGS. Any preprocessor flags (-I, -D mostly) should be in CPPFLAGS. The linker flags should be in LDFLAGS, rather than LFLAGS.

The make files work fine, so there is no hard reason to change. However using standard naming may make it easier for others to pick up the project and contribute.

HTH