I don’t think your problem has anything to do with the sqrt function.
You have obviously converted the project from C to C++ (as you are using collect2 in the link phase). This conversion has a small bug (that will be corrected soon) where link editor options set to the C project are not transfered to the C++ project (as the link editor is different).
You should add in project >> Properties >> C/C++ Build >> Settings >> MCU G++ Linker >> Miscellaneous in the appropriate text box the “-specs=nosys.specs -specs=nano.specs” settings that are provided in the C version of the project.
Alternatively you can also get the
syscalls.c file from a System Workbench-generated project and place a copy in the source folder, near your