1 files changed, 28 insertions, 0 deletions
diff --git a/build/flags-if.sh b/build/flags-if.sh
new file mode 100755
index 0000000..81eb345
--- /dev/null
+++ b/build/flags-if.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
+
+# Add flags to a makefile if a build succeeds
+
+set -eu
+
+build/cc.sh "$@" || exit 1
+
+# If the build succeeded, print any lines like
+#
+#     /// _CFLAGS += -foo
+#
+# (unless they're already set)
+OLD_FLAGS="$XCC $XCPPFLAGS $XCFLAGS $XLDFLAGS $XLDLIBS"
+
+while IFS="" read -r line; do
+    case "$line" in
+        ///*=*)
+            flag="${line#*= }"
+            if [ "${OLD_FLAGS#*"$flag"}" = "$OLD_FLAGS" ]; then
+                printf '%s\n' "${line#/// }"
+            fi
+            ;;
+    esac
+done <"$1"