Cleans up compiler flags
Cleans up compiler flags

using CXXFLAGS, LDFLAGS, LDLIBS variables which is also used by GNU
make's builtin rules. (See: https://www.gnu.org/software/make/manual/html_node/Catalogue-of-Rules.html#Catalogue-of-Rules)

HazyResearch/deepdive,closedLoop/sampler,HazyResearch/deepdive,HazyResearch/sampler,closedLoop/sampler,closedLoop/sampler,HazyResearch/deepdive,HazyResearch/sampler,HazyResearch/sampler,sai16vicky/sampler,sai16vicky/sampler,closedLoop/sampler,sai16vicky/sampler,HazyResearch/deepdive,sai16vicky/sampler