Introduce HAVE_AOUT symbol to remove hard-coded arch list for BINFMT_AOUT

HAVE_AOUT doesn't quite do the same thing as the recently removed
ARCH_SUPPORTS_AOUT config option. That was set even on platforms where
binfmt_aout isn't supported, although it's not entirely clear why.

So it's best just to introduce a new symbol, handled consistently with
other similar HAVE_xxx symbols; with a simple 'select' in the arch Kconfig.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

arch/alpha/Kconfig

@@ -5,6 +5,7 @@
 config ALPHA
 	bool
 	default y
+	select HAVE_AOUT
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	help

arch/arm/Kconfig

@@ -8,6 +8,7 @@ mainmenu "Linux Kernel Configuration"
 config ARM
 	bool
 	default y
+	select HAVE_AOUT
 	select HAVE_IDE
 	select RTC_LIB
 	select SYS_SUPPORTS_APM_EMULATION

arch/m68k/Kconfig

@@ -5,6 +5,7 @@
 config M68K
 	bool
 	default y
+	select HAVE_AOUT
 	select HAVE_IDE
 
 config MMU

arch/um/Kconfig.i386

@@ -9,8 +9,9 @@ config UML_X86
 	default y
 
 config X86_32
-       bool
-       default y
+	bool
+	default y
+  	select HAVE_AOUT
 
 config RWSEM_XCHGADD_ALGORITHM
 	def_bool y

arch/x86/Kconfig

@@ -18,6 +18,7 @@ config X86_64
 ### Arch settings
 config X86
 	def_bool y
+	select HAVE_AOUT if X86_32
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_IDE
 	select HAVE_OPROFILE

fs/Kconfig.binfmt

@@ -59,9 +59,12 @@ config BINFMT_SHARED_FLAT
 	help
 	  Support FLAT shared libraries
 
+config HAVE_AOUT
+       def_bool n
+
 config BINFMT_AOUT
 	tristate "Kernel support for a.out and ECOFF binaries"
-	depends on (X86_32 || ALPHA || ARM || M68K)
+	depends on HAVE_AOUT
 	---help---
 	  A.out (Assembler.OUTput) is a set of formats for libraries and
 	  executables used in the earliest versions of UNIX.  Linux used