C::b has no template specific for STM32. You can adopt my sample project that I posted in another thread. Link:
http://ifile.it/6wqf8i2It's for LPC1114, you have to change:
1) memory sizes in linker script
2) replace vendor-specific headers.
3) in build options word cortex-m0 to cortex-m3
4) in toolchain executables option specify linker for dynamic libs to "ld.exe", not "gcc.exe"