Compiling: Make sure that libelf is also compiled for 64bit on OS X.

--HG--
extra : convert_revision : 9d4f7064e0aa4b6cc6a5bcf0f6fb5289047cd143

ext/libelf/SConscript

@@ -88,11 +88,16 @@ ElfFile('libelf_fsize.c')
 ElfFile('libelf_msize.c')
 
 m4env = Environment(ENV=os.environ)
+
 if env.get('CC'):
     m4env['CC'] = env['CC']
 if env.get('CXX'):
     m4env['CXX'] = env['CXX']
 
+if env.get('OSX64bit'):
+    m4env.Append(CFLAGS='-arch x86_64')
+    m4env.Append(LINKFLAGS='-arch x86_64')
+
 # If we have gm4 use it
 if m4env.Detect('gm4'):
     m4env['M4'] = 'gm4'