X86: Add a configuration option to select the -m32 compiler option when needed

arch/x86/Kconfig

@@ -12,6 +12,7 @@ choice
 
 config ARCH_I486
 	bool "i486"
+	select ARCH_X86_HAVE_32BIT
 	---help---
 		Intel i486 architecture
 
@@ -19,15 +20,33 @@ endchoice
 
 config ARCH_CHIP_QEMU
 	bool "Qemu x86 emulation"
+	default n
 	---help---
 		Intel i486 architecture
 
 config ARCH_CHIP
 	string
-	default "qemu"		if ARCH_CHIP_QEMU
+	default "qemu" if ARCH_CHIP_QEMU
+
+config ARCH_X86_HAVE_32BIT
+	bool
+	default n
+
+config ARCH_X86_M32
+	bool "Build 32-bit system with a 64-bit machine"
+	default n
+	depends on ARCH_X86_HAVE_32BIT
+	---help---
+		If you are building for a 32-bit target using a native 64-bit
+		toolchain, then you need to add compilation options to select the
+		32-bit target.  Selecting this option will add the -m32 option to
+		the compiler command line.
 
 source arch/x86/src/common/Kconfig
+if ARCH_I486
 source arch/x86/src/i486/Kconfig
+endif # ARCH_I486
+if ARCH_CHIP_QEMU
 source arch/x86/src/qemu/Kconfig
-
-endif
+endif # ARCH_CHIP_QEMU
+endif # ARCH_X86