it was changed to EM_OR1K in
200d15479c0bc48471ee7b8e538ce33af990f82e
as that was meant to be the official name, but glibc and the latest
gabi spec still uses the EM_OPENRISC name:
http://www.sco.com/developers/gabi/latest/ch4.eheader.html
binutils defines both macros so we should do the same for backward
compatibility.
#define EM_MN10200 90
#define EM_PJ 91
#define EM_OR1K 92
+#define EM_OPENRISC 92
#define EM_ARC_A5 93
#define EM_XTENSA 94
#define EM_AARCH64 183