Synced with Circle Step 50.0.1

• Synced with Circle Step 50.0.1.

Full Changelog: v17.1...v17.2

AArch64 Linux is now a supported build environment

• AArch64 Linux is now a supported build environment.

Full Changelog: v17...v17.1

Update Newlib to version 4.5.0

• Updated circle-stdlib's copy of Newlib to version 4.5.0.
• Synced with Circle Step 50.
• Aligned supported toolchain version with Circle (ARM GNU toolchain 14.3.Rel1).

Full Changelog: v16.8...v17

Synced with Circle Step 49.0.1

• Fixed issue #45: The Circle library was not built in parallel mode if the top-level make
  was invoked with -j.
• Synced with Circle Step 49.0.1.
• Update Mbed TLS to release v2.28.10.

Full Changelog: v16.7...v16.8

Synced with Circle Step 49

• Synced with Circle Step 49.
• Fixed a crash in the MQTT client.

Full Changelog: v16.6...v16.7

Synced with Circle Step 48

• Synced with Circle Step 48.
• Update Mbed TLS to release v2.28.9.
• Fixed invalid payload in MQTT client.
• Fixed broken GitHub action caused by missing dependencies of the old QEMU 6.0.0 release.

Full Changelog: v16.5...v16.6

Synced with Circle Step 47

• Synced with Circle Step 47.
• Update Mbed TLS to release v2.28.8.
• Aligned toolchain version with Circle (ARM Gnu toolchain 13.2.Rel1).

Fixed issue #35

• Fixed issue #35 "No output from printf() in samples/02-stdio-hello with v16.3".

Full Changelog: v16.3...v16.4

Synced with Circle Step 46

• Synced with Circle Step 46.
• Fixed duplicate definition of fcntl().

Synced with Circle Step 45.3.1

• Synced with Circle Step 45.3.1.
• Update Mbed TLS to release v2.28.4.