Use riscv64-unknown-elf-ar in assemble.sh

riscv-rt/assemble.sh

@@ -8,14 +8,14 @@ crate=riscv-rt
 rm -f bin/*.a
 
 riscv64-unknown-elf-gcc -ggdb3 -c -mabi=ilp32 -march=rv32imac asm.S -o bin/$crate.o
-ar crs bin/riscv32imac-unknown-none-elf.a bin/$crate.o
-ar crs bin/riscv32imc-unknown-none-elf.a bin/$crate.o
+riscv64-unknown-elf-ar crs bin/riscv32imac-unknown-none-elf.a bin/$crate.o
+riscv64-unknown-elf-ar crs bin/riscv32imc-unknown-none-elf.a bin/$crate.o
 
 riscv64-unknown-elf-gcc -ggdb3 -c -mabi=ilp32 -march=rv32i asm.S -o bin/$crate.o
-ar crs bin/riscv32i-unknown-none-elf.a bin/$crate.o
+riscv64-unknown-elf-ar crs bin/riscv32i-unknown-none-elf.a bin/$crate.o
 
 riscv64-unknown-elf-gcc -ggdb3 -c -mabi=lp64 -march=rv64imac asm.S -o bin/$crate.o
-ar crs bin/riscv64imac-unknown-none-elf.a bin/$crate.o
-ar crs bin/riscv64gc-unknown-none-elf.a bin/$crate.o
+riscv64-unknown-elf-ar crs bin/riscv64imac-unknown-none-elf.a bin/$crate.o
+riscv64-unknown-elf-ar crs bin/riscv64gc-unknown-none-elf.a bin/$crate.o
 
 rm bin/$crate.o