sim: bfin: move arch-specific file compilation to top-level

The arch-specific flags are only used by the arch-specific modules,
not the common/ files, so we can delete them too.
diff --git a/sim/Makefile.in b/sim/Makefile.in
index e362113..8700a30 100644
--- a/sim/Makefile.in
+++ b/sim/Makefile.in
@@ -2047,6 +2047,7 @@
 @SIM_ENABLE_ARCH_avr_TRUE@	avr/libsim.a \
 @SIM_ENABLE_ARCH_avr_TRUE@	$(SIM_COMMON_LIBS)
 
+@SIM_ENABLE_ARCH_bfin_TRUE@AM_CPPFLAGS_bfin = $(SDL_CFLAGS)
 @SIM_ENABLE_ARCH_bfin_TRUE@bfin_libsim_a_SOURCES = 
 @SIM_ENABLE_ARCH_bfin_TRUE@bfin_libsim_a_LIBADD = \
 @SIM_ENABLE_ARCH_bfin_TRUE@	$(common_libcommon_a_OBJECTS) \
@@ -4705,9 +4706,6 @@
 @SIM_ENABLE_ARCH_avr_TRUE@	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
 @SIM_ENABLE_ARCH_bfin_TRUE@$(bfin_libsim_a_OBJECTS) $(bfin_libsim_a_LIBADD): bfin/hw-config.h
 
-@SIM_ENABLE_ARCH_bfin_TRUE@bfin/%.o: bfin/%.c
-@SIM_ENABLE_ARCH_bfin_TRUE@	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
-
 @SIM_ENABLE_ARCH_bfin_TRUE@bfin/%.o: common/%.c
 @SIM_ENABLE_ARCH_bfin_TRUE@	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
 
diff --git a/sim/bfin/Makefile.in b/sim/bfin/Makefile.in
index 569c64b..472bb48 100644
--- a/sim/bfin/Makefile.in
+++ b/sim/bfin/Makefile.in
@@ -19,6 +19,4 @@
 
 arch = bfin
 
-SIM_EXTRA_CFLAGS = $(SDL_CFLAGS)
-
 ## COMMON_POST_CONFIG_FRAG
diff --git a/sim/bfin/local.mk b/sim/bfin/local.mk
index 95bc730..d3c5b17 100644
--- a/sim/bfin/local.mk
+++ b/sim/bfin/local.mk
@@ -16,6 +16,8 @@
 ## You should have received a copy of the GNU General Public License
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+AM_CPPFLAGS_%C% = $(SDL_CFLAGS)
+
 %C%_libsim_a_SOURCES =
 %C%_libsim_a_LIBADD = \
 	$(common_libcommon_a_OBJECTS) \
@@ -33,9 +35,6 @@
 
 noinst_LIBRARIES += %D%/libsim.a
 
-%D%/%.o: %D%/%.c
-	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
-
 %D%/%.o: common/%.c
 	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)