ARM: detect VFP floating point unit

This sets HAVE_FPU correctly on ARM targets if VFP instructions are
enabled. Note that __VFP_FP__ implies the use of the VFP floating point
format, not the availability of the VFP instructions. Thus software
floating emulation __SOFTFP__ (i.e. gcc -mfloat-abi=soft) is excluded
explicitly.
(cherry picked from commit cf5a82224a3db25ed078f7d441257da51b346990)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

include/vlc_cpu.h

@@ -91,7 +91,11 @@ VLC_API unsigned vlc_CPU( void );
 #  define HAVE_FPU 1
 
 # elif defined (__arm__)
-#  define HAVE_FPU 0 /* revisit later? */
+#  if defined (__VFP_FP__) && !defined (__SOFTFP__)
+#   define HAVE_FPU 1
+#  else
+#   define HAVE_FPU 0
+#  endif
 
 # elif defined (__sparc__)
 #  define HAVE_FPU 1