message: rotating_light: added pedantic flags for GCC
  With GCC 7, there are even more diagnostic flags.
diff: @@ -51,7 +51,7 @@ doctest:
  # -Wno-keyword-macro: unit-tests use "#define private public"
  # -Wno-weak-vtables: exception class is defined inline, but has virtual method
  # -Wno-range-loop-analysis: iterator_wrapper tests tests "for(const auto i...)"
  -pedantic:
  +pedantic_clang:
  $(MAKE) json_unit CXXFLAGS="\
  -std=c++11 \
  -Werror \
  @@ -62,6 +62,66 @@ pedantic:
  -Wno-weak-vtables \
  -Wno-range-loop-analysis"
  +# calling GCC with most warnings
  +pedantic_gcc:
  + $(MAKE) json_unit CXX=g++ CXXFLAGS="\
  + -std=c++11 \
  + -Werror \
  + -Wall -Wpedantic -Wextra \
  + -Walloca \
  + -Warray-bounds=2 \
  + -Wcast-qual -Wcast-align \
  + -Wchar-subscripts \
  + -Wconditionally-supported \
  + -Wconversion \
  + -Wdate-time \
  + -Wdeprecated \
  + -Wdisabled-optimization \
  + -Wdouble-promotion \
  + -Wduplicated-branches \
  + -Wduplicated-cond \
  + -Weffc++ \
  + -Wformat-overflow=2 \
  + -Wformat-signedness \
  + -Wformat-truncation=2 \
  + -Wformat=2 \
  + -Wimplicit-fallthrough=5 \
  + -Wlogical-op \
  + -Wmissing-declarations \
  + -Wmissing-format-attribute \
  + -Wmissing-include-dirs \
  + -Wnoexcept \
  + -Wnonnull \
  + -Wnull-dereference \
  + -Wold-style-cast \
  + -Woverloaded-virtual \
  + -Wparentheses \
  + -Wplacement-new=2 \
  + -Wredundant-decls \
  + -Wreorder \
  + -Wrestrict \
  + -Wshadow=global \
  + -Wshift-overflow=2 \
  + -Wsign-conversion \
  + -Wsign-promo \
  + -Wsized-deallocation \
  + -Wstrict-overflow=5 \
  + -Wsuggest-attribute=const \
  + -Wsuggest-attribute=format \
  + -Wsuggest-attribute=noreturn \
  + -Wsuggest-attribute=pure \
  + -Wsuggest-final-methods \
  + -Wsuggest-final-types \
  + -Wsuggest-override \
  + -Wtrigraphs \
  + -Wundef \
  + -Wuninitialized -Wunknown-pragmas \
  + -Wunused \
  + -Wunused-const-variable=2 \
  + -Wunused-macros \
  + -Wunused-parameter \
  + -Wuseless-cast \
  + -Wvariadic-macros"
  ##########################################################################
  # fuzzing
  