add foundation libc to CI #158

Job	Run time
Unit Test UF2 (ubuntu-latest)	19s
Build (ubuntu-latest)	18s
Unit Test UF2 (windows-latest)	1m 0s
Unit Test Regz (ubuntu-latest)	20s
Build (windows-latest)	1m 53s
Build Examples (espressif/esp)	16s
Unit Test Regz (windows-latest)	1m 1s
Unit Test UF2 (macos-latest)	28s
Build (macos-latest)	24s
Build Examples (gigadevice/gd32)	19s
Unit Test Regz (macos-latest)	38s
Build Examples (microchip/avr)	16s
Build Website	22s
Build Examples (microchip/atsam)	18s
Dry Run Packaging	28s
Check that stm32 generated code is up to date	38s
Build Examples (nordic/nrf5x)	15s
Build Examples (nxp/lpc)	16s
Build Examples (stmicro/stm32)	16s
Unit Test Ports (ubuntu-latest, gigadevice/gd32)	22s
Validate Foundation Libc (ubuntu-latest)	18s
Build Examples (raspberrypi/rp2xxx)	16s
Unit Test Ports (ubuntu-latest, raspberrypi/rp2xxx)	32s
Validate Foundation Libc (windows-latest)	1m 31s
Unit Test Ports (ubuntu-latest, stmicro/stm32)	17s
Validate Foundation Libc (macos-latest)	18s
Unit Test Ports (windows-latest, gigadevice/gd32)	59s
Unit Test Ports (windows-latest, raspberrypi/rp2xxx)	1m 14s
Unit Test Ports (windows-latest, stmicro/stm32)	1m 2s
Unit Test Ports (macos-latest, gigadevice/gd32)	29s
Unit Test Ports (macos-latest, raspberrypi/rp2xxx)	32s
Unit Test Ports (macos-latest, stmicro/stm32)	24s
	17m 59s

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