Add a V8 specific target architecture to the GYP file...

src/globals.h

Index: src/globals.h
===================================================================
--- src/globals.h	(revision 4486)
+++ src/globals.h	(working copy)
@@ -50,15 +50,32 @@
 #define V8_HOST_ARCH_MIPS 1
 #define V8_HOST_ARCH_32_BIT 1
 #else
-#error Your host architecture was not detected as supported by v8
+#error Host architecture was not detected as supported by v8
 #endif
 
+// Check for supported combinations of host and target architectures.
+#if defined(V8_TARGET_ARCH_IA32) && !defined(V8_HOST_ARCH_IA32)
+#error Target architecture ia32 is only supported on ia32 host
+#endif
+#if defined(V8_TARGET_ARCH_X64) && !defined(V8_HOST_ARCH_X64)
+#error Target architecture x64 is only supported on x64 host
+#endif
+#if (defined(V8_TARGET_ARCH_ARM) && \
+    !(defined(V8_HOST_ARCH_IA32) || defined(V8_HOST_ARCH_ARM)))
+#error Target architecture arm is only supported on arm and ia32 host
+#endif
+#if (defined(V8_TARGET_ARCH_MIPS) && \
+    !(defined(V8_HOST_ARCH_IA32) || defined(V8_HOST_ARCH_MIPS)))
+#error Target architecture mips is only supported on mips and ia32 host
+#endif
+
+// Define unaligned read for the target architectures supporting it.
 #if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_IA32)
 #define V8_TARGET_CAN_READ_UNALIGNED 1
 #elif V8_TARGET_ARCH_ARM
 #elif V8_TARGET_ARCH_MIPS
 #else
-#error Your target architecture is not supported by v8
+#error Target architecture is not supported by v8
 #endif
 
 // Support for alternative bool type. This is only enabled if the code is