build: Allow LTO to work globally, not just codecs/plugins

IMPORTANT: There is no guarantee this will compile cleanly much less
_work_ on any given target.  This is purely to enable future hackery.

Change-Id: Ib58f21b717719fd4325622b446a60779406ae035

apps/plugins/plugins.make

@@ -154,8 +154,8 @@ endif
 PLUGINLDFLAGS += $(GLOBAL_LDOPTS)
 
 ifdef USE_LTO
- PLUGINFLAGS += -flto -fno-builtin -ffreestanding
- PLUGINLDFLAGS += -flto -fno-builtin -ffreestanding
+ PLUGINFLAGS += -fno-builtin -ffreestanding
+ PLUGINLDFLAGS += -fno-builtin -ffreestanding
  PLUGINLDFLAGS += -e plugin_start
 endif
 

firmware/firmware.make

@@ -47,6 +47,11 @@ $(BUILDDIR)/sysfont.o: $(SYSFONTX) $(BUILDDIR)/sysfont.h
 	$(call PRINTS,CONVBDF $(subst $(ROOTDIR)/,,$<))$(TOOLSDIR)/convbdf -l $(MAXCHAR) -c -o $(BUILDDIR)/sysfont.c $<
 	$(call PRINTS,CC $(subst $(ROOTDIR)/,,$(BUILDDIR)/sysfont.c))$(CC) $(CFLAGS) -c $(BUILDDIR)/sysfont.c -o $@
 
+ifdef USE_LTO
+$(BUILDDIR)/firmware/asm/%.o: CFLAGS += -fno-lto
+$(BUILDDIR)/firmware/kernel/%.o: CFLAGS += -fno-lto
+endif
+
 # GNU make (at least) has a bug/feature that exported variable are not available
 # in the shell function (but are in recipe). Thus we need to explicitely pass
 # the VERSION environement variable

lib/rbcodec/codecs/codecs.make

@@ -34,8 +34,8 @@ endif
 CODECLDFLAGS += $(GLOBAL_LDOPTS)
 
 ifdef USE_LTO
- CODECLDFLAGS += -flto -fno-builtin -ffreestanding
- CODECFLAGS += -flto -fno-builtin -ffreestanding
+ CODECLDFLAGS += -fno-builtin -ffreestanding
+ CODECFLAGS += -fno-builtin -ffreestanding
  CODECLDFLAGS += -e __header
 endif
 

tools/configure

@@ -1079,7 +1079,7 @@ S(m)all C lib, Logf to Ser(i)al port, LTO Build(X), (E)rror on warnings"
       [Xx])
         echo "LTO build enabled"
         LTO_ARG="export USE_LTO=y"
-#        GCCOPTS="$GCCOPTS -flto"
+        GCCOPTS="$GCCOPTS -flto"
         ;;
       [Ee])
         echo "Treating all warnings as errors"