If on linux amd64, compile V8 objects with -fPIC for both C and C++ files.

ext/v8/upstream/Makefile

@@ -18,6 +18,7 @@ $(SCONS): $(SCONSSRC)
 $(V8SRC): build
 	cp -r 2.0.6 build/v8
 	patch -td build/v8 -i ../../no-strict-aliasing.patch
+	patch -td build/v8 -i ../../fpic-on-linux-amd64.patch
 
 $(SCONSSRC): build
 	cp -r scons build

ext/v8/upstream/fpic-on-linux-amd64.patch

@@ -0,0 +1,13 @@
+--- SConstruct
++++ SConstruct
+@@ -139,6 +139,10 @@ LIBRARY_FLAGS = {
+       'library:shared': {
+         'CPPDEFINES': ['V8_SHARED'],
+         'LIBS': ['pthread']
++      },
++      'arch:x64': {
++        'CCFLAGS':      ['-fPIC'],
++        'CXXFLAGS':     ['-fPIC']
+       }
+     },
+     'os:macos': {