dropbear: compile with LTO enabled

Reduces size of the .ipk on MIPS from 87k to 84k

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/network/services/dropbear/Makefile

@@ -86,8 +86,8 @@ CONFIGURE_ARGS += \
 	$(if $(CONFIG_DROPBEAR_ZLIB),,--disable-zlib) \
 	--enable-bundled-libtom
 
-TARGET_CFLAGS += -DARGTYPE=3 -ffunction-sections -fdata-sections
-TARGET_LDFLAGS += -Wl,--gc-sections
+TARGET_CFLAGS += -DARGTYPE=3 -ffunction-sections -fdata-sections -flto
+TARGET_LDFLAGS += -Wl,--gc-sections -flto=jobserver
 
 define Build/Configure
 	$(Build/Configure/Default)

package/network/services/dropbear/patches/160-lto-jobserver.patch

@@ -0,0 +1,33 @@
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -163,17 +163,17 @@ dropbearkey: $(dropbearkeyobjs)
+ dropbearconvert: $(dropbearconvertobjs)
+ 
+ dropbear: $(HEADERS) $(LIBTOM_DEPS) Makefile
+-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@
++	+$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@
+ 
+ dbclient: $(HEADERS) $(LIBTOM_DEPS) Makefile
+-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS)
++	+$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS)
+ 
+ dropbearkey dropbearconvert: $(HEADERS) $(LIBTOM_DEPS) Makefile
+-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS)
++	+$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS)
+ 
+ # scp doesn't use the libs so is special.
+ scp: $(SCPOBJS)  $(HEADERS) Makefile
+-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $(SCPOBJS)
++	+$(CC) $(LDFLAGS) -o $@$(EXEEXT) $(SCPOBJS)
+ 
+ 
+ # multi-binary compilation.
+@@ -184,7 +184,7 @@ ifeq ($(MULTI),1)
+ endif
+ 
+ dropbearmulti$(EXEEXT): $(HEADERS) $(MULTIOBJS) $(LIBTOM_DEPS) Makefile
+-	$(CC) $(LDFLAGS) -o $@ $(MULTIOBJS) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@
++	+$(CC) $(LDFLAGS) -o $@ $(MULTIOBJS) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@
+ 
+ multibinary: dropbearmulti$(EXEEXT)
+