Unset grep options to prevent issues with forcing colour. Treat musl-based Linux distros are unsupported.

docs/newbs_getting_started.md

@@ -75,6 +75,8 @@ curl -fsSL https://install.qmk.fm | sh
 
 ::: info
 Many Linux distributions are supported, but not all. Mainstream distributions will have best success -- if possible, choose either Debian or its derivatives (such as Ubuntu, or Mint), CentOS or its derivatives (such as Fedora, or Rocky Linux), and Arch or its derivatives (such as Manjaro, or CachyOS).
+
+**The standard QMK build environment installed below does not support `musl`-based Linux distributions.**
 :::
 
 Install the QMK CLI by running:

util/env-bootstrap.sh

@@ -39,6 +39,10 @@
 { # this ensures the entire script is downloaded #
     set -eu
 
+    # Prevent user grep settings from injecting flags (e.g. --color=always) that
+    # corrupt captured output and break pattern matching throughout this script.
+    unset GREP_OPTIONS GREP_COLORS
+
     BOOTSTRAP_TMPDIR="$(mktemp -d /tmp/qmk-bootstrap-failure.XXXXXX)"
     trap 'rm -rf "$BOOTSTRAP_TMPDIR" >/dev/null 2>&1 || true' EXIT
     FAILURE_FILE="${BOOTSTRAP_TMPDIR}/fail"
@@ -225,6 +229,23 @@ __EOT__
         macos) echo "zstd clang-format make hidapi libusb dos2unix git" ;;
         windows) echo "base-devel: zstd:p toolchain:p clang:p hidapi:p dos2unix: git: unzip:" ;;
         linux)
+            if ldd --version 2>&1 | grep -qi musl; then
+                echo >&2
+                echo "Sorry, QMK's pre-built toolchains are compiled against glibc and will not run on musl-based Linux distributions." >&2
+                echo >&2
+                echo "Try using a glibc-based distribution, or use Docker instead:" >&2
+                echo "  - https://docs.qmk.fm/newbs_getting_started#set-up-your-environment" >&2
+                echo "  - https://docs.qmk.fm/#/getting_started_docker" >&2
+                echo >&2
+                echo "If you cannot use a compatible distro, you can try installing the \`qmk\` Python package manually using \`pip\`, most likely requiring a virtual environment:" >&2
+                echo "  % python3 -m pip install qmk" >&2
+                echo >&2
+                echo "All other dependencies will need to be installed manually, such as make, git, AVR and ARM toolchains, and associated flashing utilities." >&2
+                echo >&2
+                echo "**NOTE**: QMK does not provide official support for musl-based environments. Here be dragons, you are on your own." >&2
+                signal_execution_failure
+                return
+            fi
             case $(grep ID /etc/os-release) in
             *arch* | *manjaro* | *cachyos*) echo "zstd base-devel clang diffutils wget unzip zip hidapi dos2unix git" ;;
             *debian* | *ubuntu*) echo "zstd build-essential clang-format diffutils wget unzip zip libhidapi-hidraw0 dos2unix git" ;;