sim: mips: delete unused constant variables

Since these never change, inline and delete them.

sim/mips/configure

@@ -636,9 +636,7 @@ LIBOBJS
 sim_default_model
 sim_scache
 cgen_breaks
-mips_extra_libs
 XMKMF
-mips_igen_engine
 sim_multi_obj
 sim_multi_src
 sim_multi_igen_configs
@@ -11227,7 +11225,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11230 "configure"
+#line 11228 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11333,7 +11331,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11336 "configure"
+#line 11334 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12697,14 +12695,6 @@ fi
 
 
 
-# Choose simulator engine
-case "${target}" in
-  *)    mips_igen_engine="engine.o"
-	;;
-esac
-
-
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for X" >&5
 $as_echo_n "checking for X... " >&6; }
 
@@ -12898,8 +12888,6 @@ else
 $as_echo "libraries $x_libraries, headers $x_includes" >&6; }
 fi
 
-mips_extra_libs=""
-
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for fabs in -lm" >&5
 $as_echo_n "checking for fabs in -lm... " >&6; }