Distributions want to be able to set hardening build flags in CPPFLAGS / CXXFLAGS / LDFLAGS . The attached patch cleans up between CPPFLAGS and CXXFLAGS (the former is for the preprocessor, the latter is for the compiler, we thus want to include both in the CXX command, and LDFLAGS in the linking command), and uses ?= to let the environment provide default values.
As far as I understand, this is the same as merged pull request: https://github.com/numediart/MBROLA/pull/24
That's basically the same idea, yes