A repo that set's up an environment from scratch for stm32F4 (Linker script, startup file, makefile, ....)
I am writing an article how i start at STM32 From Scratch, you can read it here artcile
I also created a comparison table between different STM32s Here
The template_directory contains a more elaborate environment that is developed by ST ( linker file startup file and libray contains the STM32F4xx headers needed )