Tracker: GCC 7.x compatibility

[jnohlgard]

Description

This is a tracker bug for any issues which occur only with GCC version 7.x or higher. Currently the CI system is using GCC 6.x so these issues can only be seen on custom toolchain installations.

Steps to reproduce the issue

1. Install GCC 7.x, set as default compiler for your platform
2. Run make buildtest or dist/tools/compile_test/compile_test.py
3. Report any failed builds including a log of the error. Alternatively, provide a PR with the errors corrected.
4. Reference this Issue number (Tracker: GCC 7.x compatibility #8265) in the description of your Issue/PR
5. A notice will be added in this Issue automatically by Github

Issue/PR references

• unittests: Fix printf float test BUFSIZE #8243 unittests: Fix printf float test BUFSIZE
• pkg: disable implicit fallthroughs errors in tinydtls #8367 pkg: disable implicit fallthroughs errors in tinydtls
• posix: fix pthread and socket example #8368 posix: fix pthread and socket example
• examples/gnrc_tftp: fix implicit fallthrough error #8382 examples/gnrc_tftp: fix implicit fallthrough error
• pkg/ccn-lite: bump version to fix compile error #8427 pkg/ccn-lite: bump version to fix compile error
• pkg: gecko_sdk: update version for GCC7 fixes. #8554 pkg: gecko_sdk: update version for GCC7 fixes.
  • pkg/gecko_sdk: fix #8266 #8487 pkg/gecko_sdk: fix emlib: warnings when using GCC 7 #8266
  • emlib: warnings when using GCC 7 #8266 emlib: warnings when using GCC 7
• make: ignore fallthroughs errors with GCC 7.x #8430 make: ignore fallthroughs errors with GCC 7.x
• emb6: allow for warnings to be disabled #8571 emb6: allow for warnings to be disabled
• drivers/sx127x: Fix -Wmaybe-uninitialized warning #8604 drivers/sx127x: Fix -Wmaybe-uninitialized warning
• pkg/fatfs: Refactor path handling, minor fixes #8615 pkg/fatfs: Refactor path handling, minor fixes
• pkg/openthread: cleanup makefile + fix implicit-fallthrough warning #8616 pkg/openthread: cleanup + fix implicit-fallthrough warning

[smlng]

there lots of more issue regarding GCC 7.x, see this Murdock-Log where I tried to add a CI-Worker with arm-none-eabi-gcc-7.2. I'll work on fixes for these, help welcome. Tinydtls fix is provided in #8367

[cladmi]

All currently reported issues have been closed ! Cool.

[haukepetersen]

As all issues have been closed, I take the freedom to close this issue as well. Good job guys!