sim: drop use of bfd/configure.host

These settings might have made sense in darker compiler times, but I
think they're largely obsolete now.  Looking through the values that
get used in HDEFINES, it's quite limited, and configure itself should
handle them.  If we still need something, we can leverage standard
autoconf macros instead, after we get a clear user report.

TDEFINES was never set anywhere and was always empty, so prune that.

sim/or1k/configure

@@ -684,7 +684,6 @@ PACKAGE
 C_DIALECT
 RANLIB
 AR
-HDEFINES
 CC_FOR_BUILD
 INSTALL_DATA
 INSTALL_SCRIPT
@@ -8586,7 +8585,6 @@ fi
 
 
 
-
 AR=${AR-ar}
 
 if test -n "$ac_tool_prefix"; then
@@ -12950,7 +12948,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12953 "configure"
+#line 12951 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13056,7 +13054,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 13059 "configure"
+#line 13057 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13295,8 +13293,6 @@ CC="$lt_save_CC"
 
 
 
-. ${srcdir}/../../bfd/configure.host
-