[source] ar71xx: lzma loader use LTO

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/8d9ff6b6f7b2ba0c3dcba926099f819af871e0a8

commit 8d9ff6b6f7b2ba0c3dcba926099f819af871e0a8
Author: Julien Dusser <julien.dusser at free.fr>
AuthorDate: Wed Jul 19 15:45:08 2017 +0200

    ar71xx: lzma loader use LTO
    
    Change the Makefile to use LTO for better code optimisations. Gains are
    very low, only 270 bytes saved, but it's only Makefile changes.
    
    Signed-off-by: Julien Dusser <julien.dusser at free.fr>
---
 target/linux/ar71xx/image/lzma-loader/src/Makefile | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/target/linux/ar71xx/image/lzma-loader/src/Makefile b/target/linux/ar71xx/image/lzma-loader/src/Makefile
index 5f10bdb..682b31f 100644
--- a/target/linux/ar71xx/image/lzma-loader/src/Makefile
+++ b/target/linux/ar71xx/image/lzma-loader/src/Makefile
@@ -37,11 +37,13 @@ CFLAGS		= -D__KERNEL__ -Wall -Wstrict-prototypes -Wno-trigraphs -Os \
 		  -mabi=32 -march=mips32r2 \
 		  -Wa,-32 -Wa,-march=mips32r2 -Wa,-mips32r2 -Wa,--trap
 CFLAGS		+= -D_LZMA_PROB32
+CFLAGS		+= -flto
 
 ASFLAGS		= $(CFLAGS) -D__ASSEMBLY__
 
-LDFLAGS		= -static --gc-sections -no-warn-mismatch
-LDFLAGS		+= -e startup -T loader.lds -Ttext $(LZMA_TEXT_START)
+LDFLAGS		= -static -Wl,--gc-sections -Wl,-no-warn-mismatch
+LDFLAGS		+= -Wl,-e,startup -T loader.lds -Wl,-Ttext,$(LZMA_TEXT_START)
+LDFLAGS		+= -flto -fwhole-program
 
 O_FORMAT 	= $(shell $(OBJDUMP) -i | head -2 | grep elf32)
 
@@ -86,7 +88,7 @@ data.o: $(LOADER_DATA)
 	$(LD) -r -b binary --oformat $(O_FORMAT) -T lzma-data.lds -o $@ $<
 
 loader: $(OBJECTS)
-	$(LD) $(LDFLAGS) -o $@ $(OBJECTS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJECTS)
 
 loader.bin: loader
 	$(OBJCOPY) $(BIN_FLAGS) $< $@