Properly save CFLAGS and LDFLAGS before running the configure checks

    * configure: Regenerated
    * configure.ac: Properly save CFLAGS and LDFLAGS before running the
        configure checks
Added proper configuration for the STM32VLDISCOVERY and STM32F0DISCOVERY

    * config/arm/chips/stm32f051/chip.cfg: Set the CFLAGS and LDFLAGS
        for this chip
    * config/arm/chips/stm32f051/chip.ld: Example linkerscript
        specifying the memory regions for this chip
    * config/arm/chips/stm32f100/chip.cfg: Set the CFLAGS and LDFLAGS
        for this chip
    * config/arm/chips/stm32f100/chip.ld: Example linkerscript
        specifying the memory regions for this chip