Use local build when running on MinGW

Since LDFLAGS are not updated (see previous commit) we now need to
use `--with-opt-dir` option to ensure local install of SQLite3 is
used.

Author: luislavena

tasks/vendor_sqlite3.rake

@@ -28,7 +28,14 @@ def define_sqlite_task(platform, host)
 end
 
 # native sqlite3 compilation
-define_sqlite_task RUBY_PLATFORM, RbConfig::CONFIG["host"]
+recipe = define_sqlite_task(RUBY_PLATFORM, RbConfig::CONFIG["host"])
+
+# force compilation of sqlite3 when working natively under MinGW
+if RUBY_PLATFORM =~ /mingw/
+  RUBY_EXTENSION.config_options << "--with-opt-dir=#{recipe.path}"
+
+  Rake::Task['compile'].prerequisites.unshift "ports:sqlite3:#{RUBY_PLATFORM}"
+end
 
 # trick to test local compilation of sqlite3
 if ENV["USE_MINI_PORTILE"] == "true"
@@ -42,11 +49,6 @@ if ENV["USE_MINI_PORTILE"] == "true"
   Rake::Task["compile"].prerequisites.unshift "ports:sqlite3:#{RUBY_PLATFORM}"
 end
 
-# force compilation of sqlite3 when working natively under MinGW
-if RUBY_PLATFORM =~ /mingw/
-  Rake::Task['compile'].prerequisites.unshift "ports:sqlite3:#{RUBY_PLATFORM}"
-end
-
 # iterate over all cross-compilation platforms and define the proper
 # sqlite3 recipe for it.
 if RUBY_EXTENSION.cross_compile