build: Listen to make -s

1 files changed, 60 insertions, 0 deletions

diff --git a/build/msg.sh b/build/msg.sh
new file mode 100755
index 0000000..8b4714e
--- /dev/null
+++ b/build/msg.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
+
+# Print a message from a makefile:
+#
+#     $ make -s
+#     $ make
+#     [ CC ] src/main.c
+#     $ make V=1
+#     cc -Isrc -Igen -D...
+
+set -eu
+
+# Get the $MAKEFLAGS from the top-level make invocation
+MFLAGS="${XMAKEFLAGS-${MAKEFLAGS-}}"
+
+# Check if make should be quiet (make -s)
+is_quiet() {
+    # GNU make puts single-letter flags in the first word of $MAKEFLAGS,
+    # without a leading dash
+    case "${MFLAGS%% *}" in
+        -*) : ;;
+        *s*) return 0 ;;
+    esac
+
+    # BSD make puts each flag separately like -r -s -j 48
+    for flag in $MFLAGS; do
+        case "$flag" in
+            # Ignore things like --jobserver-auth
+            --*) continue ;;
+            -*s*) return 0 ;;
+        esac
+    done
+
+    return 1
+}
+
+# Check if make should be loud (make V=1)
+is_loud() {
+    test "$XV"
+}
+
+MSG="$1"
+shift
+
+if ! is_quiet && ! is_loud; then
+    printf '%s\n' "$MSG"
+fi
+
+if [ $# -eq 0 ]; then
+    exit
+fi
+
+if is_loud; then
+    printf '%s\n' "$*"
+fi
+
+"$@"