add -fPIC on linux x64 build

Rakefile

@@ -22,6 +22,7 @@ task :checkout do
   # Fix gyp trying to build platform-linux on FreeBSD 9 and FreeBSD 10.
   # Based on: https://chromiumcodereview.appspot.com/10079030/patch/1/2
   sh "patch -N -p0 -d vendor/v8 < patches/add-freebsd9-and-freebsd10-to-gyp-GetFlavor.patch"
+  sh "patch -N -p1 -d vendor/v8 < patches/fPIC-on-linux-x64.patch"
 end
 
 desc "compile v8 via the ruby extension mechanism"

patches/fPIC-on-linux-x64.patch

@@ -0,0 +1,14 @@
+diff --git a/build/standalone.gypi b/build/standalone.gypi
+index ebdf557..c7a59bc 100644
+--- a/build/standalone.gypi
++++ b/build/standalone.gypi
+@@ -98,6 +98,9 @@
+           [ 'OS=="linux"', {
+             'cflags': [ '-ansi' ],
+           }],
++          [ 'OS=="linux" and v8_target_arch=="x64" and component=="static_library"', {
++            'cflags': [ '-fPIC', ],
++          }],
+           [ 'visibility=="hidden"', {
+             'cflags': [ '-fvisibility=hidden' ],
+           }],