tools: Simplify BITS_PER_LONG define

Do it using (__CHAR_BIT__ * __SIZEOF_LONG__), simpler, works everywhere,
reduces the complexity by ditching CONFIG_64BIT, that was being
synthesized from yet another set of defines, which proved fragile,
breaking the build on linux-next for no obvious reasons.

Committer Note:

Except on:

gcc version 4.1.2 20080704 (Red Hat 4.1.2-55)

Fallback to __WORDSIZE in that case...

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160715072243.GP30154@twins.programming.kicks-ass.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/include/asm-generic/bitsperlong.h

@@ -3,31 +3,12 @@
 
 #include <uapi/asm-generic/bitsperlong.h>
 
-/*
- * In the kernel, where this file comes from, we can rely on CONFIG_64BIT,
- * here we have to make amends with what the various compilers provides us
- * to figure out if we're on a 64-bit machine...
- */
 #ifdef __SIZEOF_LONG__
-# if __SIZEOF_LONG__ == 8
-#  define CONFIG_64BIT
-# endif
+#define BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
 #else
-# ifdef __WORDSIZE
-#  if __WORDSIZE == 64
-#   define CONFIG_64BIT
-#  endif
-# else
-#  error Failed to determine BITS_PER_LONG value
-# endif
+#define BITS_PER_LONG __WORDSIZE
 #endif
 
-#ifdef CONFIG_64BIT
-#define BITS_PER_LONG 64
-#else
-#define BITS_PER_LONG 32
-#endif /* CONFIG_64BIT */
-
 #if BITS_PER_LONG != __BITS_PER_LONG
 #error Inconsistent word size. Check asm/bitsperlong.h
 #endif