[PATCH] Makefile: Add -fuse-ld for merge_objs

[Xiang W]

On some platforms, the default linker is `mold`, which can cause the
following error. Adding the `--fuse-ld` option can prevent this problem.

    MERGE     platform/generic/firmware/payloads/test.o
    mold: fatal: unknown command line option: -b elf64-littleriscv

Signed-off-by: Xiang W <wangxiang at iscas.ac.cn>
---
 Makefile | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index eb95164c..a8d702a1 100644
--- a/Makefile
+++ b/Makefile
@@ -433,13 +433,16 @@ ELFFLAGS	+=	-Wl,--no-dynamic-linker -Wl,-pie
 ELFFLAGS	+=	$(platform-ldflags-y)
 ELFFLAGS	+=	$(firmware-ldflags-y)
 
-MERGEFLAGS	+=	-r
+MERGEFLAGS	+=	$(USE_LD_FLAG)
+MERGEFLAGS	+=	-no-pie
+MERGEFLAGS	+=	-nostdlib
+MERGEFLAGS	+=	-Wl,-r
 ifeq ($(LD_IS_LLD),y)
-MERGEFLAGS	+=	-b elf
+MERGEFLAGS	+=	-Wl,-b,elf
 else
-MERGEFLAGS	+=	-b elf$(PLATFORM_RISCV_XLEN)-littleriscv
+MERGEFLAGS	+=	-Wl,-b,elf$(PLATFORM_RISCV_XLEN)-littleriscv
 endif
-MERGEFLAGS	+=	-m elf$(PLATFORM_RISCV_XLEN)lriscv
+MERGEFLAGS	+=	-Wl,-m,elf$(PLATFORM_RISCV_XLEN)lriscv
 
 DTSCPPFLAGS	=	$(CPPFLAGS) -nostdinc -nostdlib -fno-builtin -D__DTS__ -x assembler-with-cpp
 
@@ -459,7 +462,7 @@ define dynamic_flags
 endef
 merge_objs = $(CMD_PREFIX)mkdir -p `dirname $(1)`; \
 	     echo " MERGE     $(subst $(build_dir)/,,$(1))"; \
-	     $(LD) $(MERGEFLAGS) $(2) -o $(1)
+	     $(CC) $(MERGEFLAGS) $(2) -o $(1)
 merge_deps = $(CMD_PREFIX)mkdir -p `dirname $(1)`; \
 	     echo " MERGE-DEP $(subst $(build_dir)/,,$(1))"; \
 	     cat $(2) > $(1)
-- 
2.47.3