Fix order ldflags

[paugier]

Fix a bug (native with -lm) by changing ldflags order: -lm last.

The PR contains a failing test and a very simple fix. The error produced by pytest spy/tests/compiler/test_native.py:

E           FAILED: test 
E           cc src/test.o src/_print.o -o test -lm -L /home/pierre/dev/spy/spy/libspy/build/native/debug -lspy
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/build/native/debug/libspy.a(operator.o): in function `spy_operator$f32_floordiv':
E           /home/pierre/dev/spy/spy/libspy/src/operator.c:50: undefined reference to `floorf'
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/build/native/debug/libspy.a(operator.o): in function `spy_unsafe$f32_unchecked_floordiv':
E           /home/pierre/dev/spy/spy/libspy/src/operator.c:60: undefined reference to `floorf'
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/build/native/debug/libspy.a(operator.o): in function `spy_operator$f32_mod':
E           /home/pierre/dev/spy/spy/libspy/src/operator.c:68: undefined reference to `fmodf'
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/build/native/debug/libspy.a(operator.o): in function `spy_unsafe$f32_unchecked_mod':
E           /home/pierre/dev/spy/spy/libspy/src/operator.c:84: undefined reference to `fmodf'
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/build/native/debug/libspy.a(operator.o): in function `spy_operator$f32_pow':
E           /home/pierre/dev/spy/spy/libspy/src/operator.c:135: undefined reference to `truncf'
E           /usr/bin/ld: /home/pierre/dev/spy/spy/libspy/src/operator.c:138: undefined reference to `powf'
E           collect2: error: ld returned 1 exit status