It's possible that I simply don't understand the required intricacies of building with CMake. If so I apologise.

What am I doing
At my company we use libmongoc/libbson on different flavors of Ubuntu and Windows 10. We link statically against both libs because we want to keep the number of redistributables down to a minimum. MongoC and BSON are in most cases linked against a shared library which we distribute in-house. This was a breeze with 1.9.2 using automake, but seems to be slightly broken in 1.14.0 (possibly other versions as well).

Problem 1 (I consider this as being slightly broken)
Using the following CMake command, followed by make && make install results in static libraries that cannot be linked together since libmongoc-static-1.0.a will contain symbols that are also present in libbson-static-1.0.a.

CFLAGS=-fPIC CXXFLAGS=-fPIC cmake -DENABLE_ZLIB=BUNDLED -DENABLE_AUTOMATIC_INIT_AND_CLEANUP=OFF -DENABLE_EXAMPLES=OFF -DENABLE_TESTS=OFF -DCMAKE_BUILD_TYPE=Release ../

The offending symbols are

bson_b64_initialize_rmap
bson_b64_ntop
bson_b64_pton
_bson_md5_append
_bson_md5_finish
_bson_md5_init
bson_md5_process

And the symptom of which is multiple definition errors when linking libmongoc and libbson against my artifact(s).
The workaround I ended up with here is to use objcopy to weaken the symbols in libmongoc-static-1.0.a post-build, before creating an archive and uploading it to our internal artifact storage for general consumption.

objcopy --weaken-symbol bson_b64_initialize_rmap --weaken-symbol bson_b64_ntop --weaken-symbol bson_b64_pton --weaken-symbol _bson_md5_append --weaken-symbol _bson_md5_finish --weaken-symbol _bson_md5_init --weaken-symbol bson_md5_process some_path_to/lib/libmongoc-static-1.0.a

Problem 2 (minor, but annoying)
Using the following CMake command, followed by make && make install results in static libraries that do not support relocation (i.e no -fPIC) and thus cannot be linked against a shared object.

cmake -DENABLE_ZLIB=BUNDLED -DENABLE_AUTOMATIC_INIT_AND_CLEANUP=OFF -DENABLE_EXAMPLES=OFF -DENABLE_TESTS=OFF  -DCMAKE_BUILD_TYPE=Release ../

The workaround I used here was to simply set CFLAGS=-fPIC CXXFLAGS=-fPIC, but it would be nice if there was a proper build flag for setting them. Like ENABLE_PIC or something along those lines.

Problem 3 (confusing)
The libraries produced by building the CMake projects are not properly versioned. It's been 1.0 since forever.

The workaround for problem 1 seems overly hackish just to be able to use the static libraries. I'm not sure how you'd fix it in a proper manner since I'm not very familiar with mongoc's CMake setup. Is there to your knowledge a better way to achieve this than my current workaround? Would it be possible to get it fixed at your end so that I don't have to feel so dirty using objcopy?

Thanks!