Remove unnecessary build flags

Author: KitaitiMakoto

bindings/ruby/ext/extconf.rb

@@ -43,8 +43,6 @@ def tsort_each_child(node, &block)
  .reverse
  .join(" ")
 
-$CFLAGS << " -std=c11 -fPIC"
-$CXXFLAGS << " -std=c++17 -O3 -DNDEBUG"
 $INCFLAGS << " -Isources/include -Isources/ggml/include -Isources/examples"
 $LOCAL_LIBS << " #{libs}"
 $cleanfiles << " build #{libs}"