Remove arch loops from build scripts. (#889)

This simplifies non-sdk build scripts by removing their loops over SM.archs. Instead the top-level
build script will re-evaluate them for each architecture.

extensions/geoip/AMBuilder

@@ -1,20 +1,18 @@
 # vim: set sts=2 ts=8 sw=2 tw=99 et ft=python:
 import os
 
-for arch in SM.archs:
-  binary = SM.ExtLibrary(builder, 'geoip.ext', arch)
-  if binary.compiler.family == 'gcc' or binary.compiler.family == 'clang':
-    binary.compiler.cxxflags += ['-fno-rtti']
-  elif binary.compiler.family == 'msvc':
-    binary.compiler.cxxflags += ['/GR-']
-  if builder.target.platform == 'windows':
-    binary.compiler.postlink += ['wsock32.lib']
+binary = SM.ExtLibrary(builder, 'geoip.ext', arch)
+if binary.compiler.family == 'gcc' or binary.compiler.family == 'clang':
+  binary.compiler.cxxflags += ['-fno-rtti']
+elif binary.compiler.family == 'msvc':
+  binary.compiler.cxxflags += ['/GR-']
+if builder.target.platform == 'windows':
+  binary.compiler.postlink += ['wsock32.lib']
 
-  binary.sources += [
-    'extension.cpp',
-    'GeoIP.c',
-    '../../public/smsdk_ext.cpp'
-  ]
-
-  SM.extensions += [builder.Add(binary)]
+binary.sources += [
+  'extension.cpp',
+  'GeoIP.c',
+  '../../public/smsdk_ext.cpp'
+]
 
+SM.extensions += [builder.Add(binary)]