Add ABFD argument to sim_open call. Pass through to sim_config so

that image properties such as endianness can be checked.

More strongly document the expected behavour of each of the sim_*
interfaces.

Add default endian argument to simulator config macro
SIM_AC_OPTION_ENDIAN.  Use in sim_config.

sim/configure

@@ -1273,6 +1273,7 @@ fi
 # Assume simulator can be built with cc.
 # If the user passes --enable-sim built it regardless of $(CC).
 only_if_gcc=no
+only_if_enabled=no
 extra_subdirs=common
 
 # WHEN ADDING ENTRIES TO THIS MATRIX:
@@ -1292,6 +1293,7 @@ case "${target}" in
 # end-sanitize-d30v
   h8300*-*-*)		sim_target=h8300 ;;
   h8500-*-*)		sim_target=h8500 ;;
+  m32r-*-*)		sim_target=m32r ;;
   mips*-*-*)
 	# The MIPS simulator can only be compiled by gcc.
 	sim_target=mips
@@ -1328,6 +1330,20 @@ case "${target}" in
 	only_if_gcc=yes
 	;;
 # end-sanitize-v850
+# start-sanitize-v850e
+  v850e-*-*)
+	# The V850 simulator can only be compiled by gcc.
+	sim_target=v850
+	only_if_gcc=yes
+	;;
+# end-sanitize-v850e
+# start-sanitize-v850eq
+  v850eq-*-*)
+	# The V850 simulator can only be compiled by gcc.
+	sim_target=v850
+	only_if_gcc=yes
+	;;
+# end-sanitize-v850eq
   w65-*-*)		sim_target=w65 ;;
   z8k*-*-*)		sim_target=z8k ;;
   sparc64-*-*)
@@ -1337,6 +1353,9 @@ case "${target}" in
 	# The SPARC simulator can only be compiled by gcc.
 	sim_target=erc32
 	only_if_gcc=yes
+	# Unfortunately erc32 won't build on many hosts, so only enable
+	# it if the user really really wants it.
+	only_if_enabled=yes
 	;;
   *)			sim_target=none ;;
 esac
@@ -1352,9 +1371,13 @@ yes)
 	fi
 	;;
 *)
-	if test ${only_if_gcc} = yes ; then
-		if test "${GCC}" != yes ; then
-			sim_target=none
+	if test ${only_if_enabled} = yes ; then
+		sim_target=none
+	else
+		if test ${only_if_gcc} = yes ; then
+			if test "${GCC}" != yes ; then
+				sim_target=none
+			fi
 		fi
 	fi
 	;;