[DEBUG]  Testing '! ( -n  )'
[INFO ]  Performing some trivial sanity checks
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Testing '! ( -n  )'
[DEBUG]  Sanitized 'CT_INSTALL_DIR': '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/' -> '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/'
[WARN ]  Number of open files 1024 may not be sufficient to build the toolchain; increasing to 2048
[DEBUG]  ==> Executing:  'mkdir' '-p' '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/.build'
[DEBUG]  ==> Return status 0
[DEBUG]  ==> Executing:  'rm' '-f' '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/.build/backtrace'
[DEBUG]  ==> Return status 0
[DEBUG]  ==> Executing:  'touch' '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/.build/foo'
[DEBUG]  ==> Return status 0
[DEBUG]  Testing '! ( -f /mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/.build/FOO )'
[ERROR]  Your file system in '/mnt/d/embedded_linux_course/toolchain_understanding/crosstool-ng/.build' is *not* case-sensitive!
[ERROR]
[ERROR]  >>
[ERROR]  >>  Build failed in step '(top-level)'
[ERROR]  >>
[ERROR]  >>  Error happened in: CT_Abort[scripts/functions@487]
[ERROR]  >>        called from: CT_TestAndAbort[scripts/functions@507]
[ERROR]  >>        called from: main[scripts/crosstool-NG.sh@123]
[ERROR]  >>
[ERROR]  >>  For more info on this error, look at the file: 'build.log'
[ERROR]  >>  There is a list of known issues, some with workarounds, in:
[ERROR]  >>      https://crosstool-ng.github.io/docs/known-issues/
[ERROR]  >>
[ERROR]  >>  If you feel this is a bug in crosstool-NG, report it at:
[ERROR]  >>      https://github.com/crosstool-ng/crosstool-ng/issues/