Fix compilation of arm-linux-user target.

[rmalmain]

Fix for #53.

There seems to be a linking issue with the unit tests @aurelf, can you have a look?

FAILED: tests/unit/check-sym-runtime
cc -m64 -mcx16  -o tests/unit/check-sym-runtime tests/unit/check-sym-runtime.p/check-sym-runtime.c.o -Wl,--as-needed -Wl,--no-undefined -pie -Wl,--whole-archive libevent-loop-base.fa libqom.fa libhwcore.fa -Wl,--no-whole-archive -fsanitize=undefined -fsanitize=address -fstack-protector-strong -Wl,-z,relro -Wl,-z,now -Wl,--warn-common -Wl,-rpath,/home/rmalmain/Projects/symcc/symcc/build/SymRuntime-prefix/src/SymRuntime-build -Wl,-rpath-link,/home/rmalmain/Projects/symcc/symcc/build/SymRuntime-prefix/src/SymRuntime-build libqemu-arm-linux-user.fa -Wl,--start-group libqemuutil.a libevent-loop-base.fa libqom.fa libhwcore.fa /home/rmalmain/Projects/symcc/symcc/build/SymRuntime-prefix/src/SymRuntime-build/libSymRuntime.so /usr/lib/libz.so /usr/lib/libcapstone.so /usr/lib/libdw.so /usr/lib/libelf.so -Xlinker --dynamic-list=/home/rmalmain/Projects/symqemu/symqemu-official/plugins/qemu-plugins.symbols -lrt -lm -pthread /usr/lib/libglib-2.0.so /usr/lib/libgmodule-2.0.so -Wl,--end-group
/usr/bin/ld: libqemu-arm-linux-user.fa.p/linux-user_main.c.o:/home/rmalmain/Projects/symqemu/symqemu-official/build/../linux-user/main.c:82: multiple definition of `guest_base'; tests/unit/check-sym-runtime.p/check-sym-runtime.c.o:/home/rmalmain/Projects/symqemu/symqemu-official/build/../tests/unit/check-sym-runtime.c:29: first defined here
/usr/bin/ld: libqemu-arm-linux-user.fa.p/linux-user_main.c.o: in function `main':
/home/rmalmain/Projects/symqemu/symqemu-official/build/../linux-user/main.c:674: multiple definition of `main'; tests/unit/check-sym-runtime.p/check-sym-runtime.c.o:/home/rmalmain/Projects/symqemu/symqemu-official/build/../tests/unit/check-sym-runtime.c:367: first defined here
/usr/bin/ld: libqemu-arm-linux-user.fa.p/linux-user_main.c.o:(.bss+0x1424): multiple definition of `__odr_asan.guest_base'; tests/unit/check-sym-runtime.p/check-sym-runtime.c.o:(.bss+0x40): first defined here
/usr/bin/ld: libcommon.fa.p/gdbstub_syscalls.c.o: warning: relocation against `gdbserver_state' in read-only section `.text.unlikely'
/usr/bin/ld: libqemu-arm-linux-user.fa.p/accel_tcg_tb-maint.c.o: in function `do_tb_flush':
/home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/tb-maint.c:776:(.text+0x228): undefined reference to `tcg_region_reset_all'
/usr/bin/ld: libqemu-arm-linux-user.fa.p/accel_tcg_translate-all.c.o: in function `setjmp_gen_code':
/home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:271:(.text+0x989): undefined reference to `tcg_ctx'
/usr/bin/ld: /home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:276:(.text+0x9e9): undefined reference to `tcg_ctx'
/usr/bin/ld: /home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:276:(.text+0x9f2): undefined reference to `tcg_func_start'
/usr/bin/ld: /home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:281:(.text+0xae1): undefined reference to `tcg_ctx'
/usr/bin/ld: /home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:284:(.text+0xbc7): undefined reference to `tcg_ctx'
/usr/bin/ld: /home/rmalmain/Projects/symqemu/symqemu-official/build/../accel/tcg/translate-all.c:284:(.text+0xbd0): undefined reference to `tcg_gen_code'

[aurelf]

Duplicate of PR #57