Bug Report

Current behavior

Tested with LANG=de_DE.UTF-8:

Compilation of a project from Arduino IDE or from the command line fails because the necessary include paths (for used libraries) are not appended to the g++ command. The auto-detection does not work properly because it expects a hard-coded string, which is not present in the compiler output in all locales.

Expected behavior

Compilation works independently from the current locale.

The code should set LC_MESSAGES before executing g++.

Environment

• CLI version (output of arduino-cli version):
  tested with arduino-builder-1.5.4, which links arduino-cli as of 2020年06月12日T15:26:41-00:00 (3b18571).

• OS and platform:
  tested on a Gentoo system.

Additional context

Hard-coded error message is in legacy/builder/includes_finder_with_regexp.go. The regular expression may be safe and match in all locales. However, the (more) correct way is to run the compiler in a known locale (POSIX or C at best, because a machine will be reading the output).