message: fix adios2-config help (--cxx instead of -cxx)
diff: @@ -6,7 +6,7 @@ function usage() {
  echo " -c Both compile and link flags for the C bindings"
  echo " --c-flags Preprocessor and compile flags for the C bindings"
  echo " --c-libs Linker flags for the C bindings"
  - echo " -x, -cxx Both compile and link flags for the C++ bindings"
  + echo " -x, --cxx Both compile and link flags for the C++ bindings"
  echo " --cxx-flags Preprocessor and compile flags for the C++ bindings"
  echo " --cxx-libs Linker flags for the C++ bindings"
  echo " -f, --fortran Both compile and link flags for the F90 bindings"
  