wip: update to latest mini_portile and drop the pkgconf hacks

See flavorjones/mini_portile#131

Gemfile

@@ -9,3 +9,5 @@ gem("rdoc", "6.5.0")
 gem("psych", "5.1.0")
 
 gem("ruby_memcheck", "2.1.2") if Gem::Platform.local.os == "linux"
+
+gem "mini_portile2", git: "https://github.com/flavorjones/mini_portile", ref: "74ac5a11"

ext/sqlite3/extconf.rb

@@ -66,28 +66,6 @@ def configure_packaged_libraries
             recipe.cook
           end
           recipe.activate
-
-          # on macos, pkg-config will not return --cflags without this
-          ENV["PKG_CONFIG_ALLOW_SYSTEM_CFLAGS"] = "t"
-
-          # only needed for Ruby 3.1.3, see https://bugs.ruby-lang.org/issues/19233
-          RbConfig::CONFIG["PKG_CONFIG"] = config_string("PKG_CONFIG") || "pkg-config"
-
-          lib_path = File.join(recipe.path, "lib")
-          pcfile = File.join(lib_path, "pkgconfig", "sqlite3.pc")
-          abort_pkg_config("pkg_config") unless pkg_config(pcfile)
-
-          # see https://bugs.ruby-lang.org/issues/18490
-          ldflags = xpopen(["pkg-config", "--libs", "--static", pcfile], err: [:child, :out], &:read)
-          abort_pkg_config("xpopen") unless $?.success?
-          ldflags = ldflags.split
-
-          # see https://github.com/flavorjones/mini_portile/issues/118
-          "-L#{lib_path}".tap do |lib_path_flag|
-            ldflags.prepend(lib_path_flag) unless ldflags.include?(lib_path_flag)
-          end
-
-          ldflags.each { |ldflag| append_ldflags(ldflag) }
         end
       end