A build issue happens when building the tfm source code cloned from git May-15 in Windows environment using a Keil MDK pro (ARMCLANG, Arm tools V6.7) Single-User License setup (Win 10, Cygwin, CMake).
According to the instructions found in the tfm repo Keil users shall set ARM_TOOL_VARIANT, ARM_PRODUCT_PATH and ARMLMD_LICENSE_FILE. However, this does not work in the my setup.
If ARM_TOOL_VARIANT, ARM_PRODUCT_PATH and ARMLMD_LICENSE_FILE are unassigned CMake and make complete without errors, although that CMake provides warnings (messages) indicating that "...ARM_TOOL_VARIANT or ARM_PRODUCT_PATH environment variables are not set".
So I propose that at least a note about this detail is added to section "Setup Cygwin to enable a compiler toolchain and cmake after installation", something like:
"In Keil Single-User License configurations the environment variables ARM_TOOL_VARIANT, ARMLMD_LICENSE_FILE and ARM_PRODUCT_PATH shall not be set."