boost: Improve reproducibility
Set .file section explicitly for .S files to avoid
the linker introduces the host path in symbols for
object files whose source file is .S
Otherwise, there is a host path in the symbols as
below:
$ readelf --wide --symbols /my-build/boost/1.67.0-r0/boost_1_67_0/x86_64-poky-linux/boost/bin.v2/libs/context/build/
aca09349fdb84d131321425f6c3a38ed/libboost_context.so.1.67.0
42:
0000000000000000 0 FILE LOCAL DEFAULT ABS /my-build/boost/1.67.0-r0/boost_1_67_0/x86_64-poky-linux/boost/bin.v2/libs/context/build/
aca09349fdb84d131321425f6c3a38ed/asm/make_x86_64_sysv_elf_gas.o
[YOCTO #12708]
Signed-off-by: Mingli Yu <Mingli.Yu@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
