libmicrokit: fix to successfully link on LLD

LLD does not recognise the STARTUP directive which works with the
GNU linker. Given that the crt0.s entry point is already specified
to be at the start of the _text section when linking with libmicrokit,
all we need to do is slightly change the Makefile to also include
crt0.o when linking to produce libmicrokit.a

Signed-off-by: Ivan Velickovic <[email protected]>

libmicrokit/Makefile

@@ -15,8 +15,7 @@ TOOLCHAIN := aarch64-none-elf-
 CFLAGS := -std=gnu11 -g3 -O3 -nostdlib -ffreestanding -mcpu=$(GCC_CPU) -Wall -Wno-maybe-uninitialized -Wno-unused-function -Werror -Iinclude -I$(SEL4_SDK)/include
 
 LIBS := libmicrokit.a
-OBJS := main.o dbg.o
-OTHER_OBJS :=  crt0.o
+OBJS := main.o crt0.o dbg.o
 
 $(BUILD_DIR)/%.o : src/%.S
 	$(TOOLCHAIN)gcc -x assembler-with-cpp -c -g3  -mcpu=$(GCC_CPU)  $< -o $@
@@ -29,7 +28,7 @@ $(BUILD_DIR)/%.o : src/%.c
 
 LIB = $(addprefix $(BUILD_DIR)/, $(LIBS))
 
-all: $(LIB) $(addprefix $(BUILD_DIR)/, $(OTHER_OBJS))
+all: $(LIB)
 
 $(LIB): $(addprefix $(BUILD_DIR)/, $(OBJS))
 	$(TOOLCHAIN)ar -rv $@ $^

libmicrokit/microkit.ld

@@ -11,8 +11,6 @@ PHDRS
 
 ENTRY(_start);
 
-STARTUP(crt0.o);
-
 SECTIONS
 {
     . = 0x200000;