elf.h: new elf header flag to mark 2008-NaN vs legacy-NaN on mips

see glibc commit 9c21573c02446b3d5cf6a34b67c8545e5be6a600

include/elf.h

@@ -1153,6 +1153,7 @@ typedef struct {
 #define EF_MIPS_64BIT_WHIRL 16
 #define EF_MIPS_ABI2	    32
 #define EF_MIPS_ABI_ON32    64
+#define EF_MIPS_NAN2008     1024
 #define EF_MIPS_ARCH	    0xf0000000