extconf.rb in fasttext-0.2.1

- old
+ new

@@ -1,8 +1,8 @@
 require "mkmf-rice"
 
 # -pthread and -O3 set by default
-$CXXFLAGS << " -std=c++17 -funroll-loops " << with_config("optflags", "-march=native")
+$CXXFLAGS << " -std=c++17 $(optflags) -funroll-loops " << with_config("optflags", "-march=native")
 
 ext = File.expand_path(".", __dir__)
 fasttext = File.expand_path("../../vendor/fastText/src", __dir__)
 
 $srcs = Dir["{#{ext},#{fasttext}}/*.{cc,cpp}"]