Consistently adjust FD_SETSIZE on all extensions

Previously only `rubyeventmachine` FD were adjusted. Just to be consistent
all compiled extensions should be doing the same.

ext/fastfilereader/extconf.rb

@@ -26,6 +26,15 @@ def add_define(name)
   add_define 'OS_UNIX'
 end
 
+# Adjust number of file descriptors (FD) on Windows
+
+if RbConfig::CONFIG["host_os"] =~ /mingw/
+  found = RbConfig::CONFIG.values_at("CFLAGS", "CPPFLAGS").
+    any? { |v| v.include?("FD_SETSIZE") }
+
+  add_define "FD_SETSIZE=32767" unless found
+end
+
 # Main platform invariances:
 
 case RUBY_PLATFORM
@@ -91,4 +100,4 @@ def add_define(name)
   CONFIG['LDSHARED'] = "$(CXX) -shared"
 end
 
-create_makefile "fastfilereaderext"
+create_makefile "fastfilereaderext"