I run Asterisk on OpenSuse Leap 15. The highest version of libjansson-devel available for this O/S is 2.9 and therefore I have to use --with-jansson-bundled. Configure runs OK and when I ‘make’ the system it correctly compiles the bundled jansson. However it places the compiled files into third-party/jansson/dest/lib64 and when compiling main the loader can’t find ‘json_vsprintf’ because it looks in third-party/jansson/dest/lib. By copying (or linking) dest/lib64 to dest/lib the compile works OK.
This may be something to do with OpenSuse settings but if it is I don’t know where to find them. As the compile finishes OK with this workaround I am assuming the Asterisk will work OK.