>  dpkg-gensymbols: warning: some new symbols appeared in the symbols file: see diff output below
>  dpkg-gensymbols: warning: debian/libbson-1.0-0/DEBIAN/symbols doesn't match completely debian/libbson-1.0-0.symbols
>  --- debian/libbson-1.0-0.symbols (libbson-1.0-0_1.3.5-1_mipsel)
>  +++ dpkg-gensymbolsWR4fxq    2016-05-17 18:25:54.650806227 +0000
>  @@ -43,6 +43,7 @@
>    bson_array_as_json@LIBBSON_1.0 1.2.1
>    bson_as_json@LIBBSON_1.0 1.2.1
>    bson_ascii_strtoll@LIBBSON_1.0 1.2.1
>  + bson_atomic_int64_add@LIBBSON_1.0 1.3.5-1
>    bson_bcon_magic@LIBBSON_1.0 1.2.1
>    bson_bcone_magic@LIBBSON_1.0 1.2.1
>    bson_check_version@LIBBSON_1.2 1.2.1

The problem is in bson-atomic.h file, where bson_atomic_int64_add is defined.

>  define bson_atomic_int64_add(p, v) __sync_add_and_fetch((volatile int64_t*)(p), (int64_t)(v))

Mips platform does not have 64-bit __sync_* operations.
To avoid this behaviour it is needed to use
corresponding __atomic_* from libatomic library.

Patch use-atomic-instead-sync.patch contains these changes
of src/bson/bson-atomic.h and build/autotools/CheckAtomics.m4.

The patch is tested on mips, mipsel, mips64el, amd64 and i386.
With this patch, package builds successfully.

Regards,
Radovan