build: enable strict aliasing if gcc < 4.5.0

We already enable -fstrict-aliasing when gcc >= 4.6.0 but let's enable it for
gcc < 4.5.0 as well. The aliasing bugs that we ran into in the past are all
particular to the 4.5.x releases.

common.gypi

@@ -1,6 +1,6 @@
 {
   'variables': {
-    'strict_aliasing%': 'false',     # turn on/off -fstrict-aliasing
+    'node_no_strict_aliasing%': 0,   # turn off -fstrict-aliasing
     'visibility%': 'hidden',         # V8's visibility setting
     'target_arch%': 'ia32',          # set v8's target architecture
     'host_arch%': 'ia32',            # set v8's host architecture
@@ -52,7 +52,7 @@
             # pull in V8's postmortem metadata
             'ldflags': [ '-Wl,-z,allextract' ]
           }],
-          ['strict_aliasing!="true"', {
+          ['node_no_strict_aliasing==1', {
             'cflags': [ '-fno-strict-aliasing' ],
           }],
         ],

configure

@@ -267,15 +267,12 @@ def configure_node(o):
 
   is_llvm, is_clang, cc_version = compiler_version()
 
-  # turn off strict aliasing if gcc < 4.6.0 unless it's llvm-gcc
+  # turn off strict aliasing if gcc >= 4.5.0 && < 4.6.0 unless it's clang
   # see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45883
   # see http://code.google.com/p/v8/issues/detail?id=884
-  o['variables']['strict_aliasing'] = b(is_clang or cc_version >= (4,6,0))
-
-  # disable strict aliasing in V8 if we're compiling with gcc 4.5.x,
-  # it makes V8 crash in various ways
-  o['variables']['v8_no_strict_aliasing'] = b(
-    not is_clang and (4,5,0) <= cc_version < (4,6,0))
+  no_strict_aliasing = (4,5,0) <= cc_version < (4,6,0) and not is_clang
+  o['variables']['node_no_strict_aliasing'] = int(no_strict_aliasing)
+  o['variables']['v8_no_strict_aliasing'] = int(no_strict_aliasing)
 
   # clang has always supported -fvisibility=hidden, right?
   if not is_clang and cc_version < (4,0,0):