kc3-lang/kc3

diff --git a/config.subr b/config.subr
index 591d814..0259b5c 100644
--- a/config.subr
+++ b/config.subr
@@ -176,7 +176,11 @@ config_asan() {
     OUT=".config_$NAME"
     echo "/* generated by configure */" > "$OUT_C"
     echo "#include <stdlib.h>" >> "$OUT_C"
-    echo "int main (void) { (void) malloc(1); return 0; }" >> "$OUT_C"
+    echo "int main (void) {" >> "$OUT_C"
+    echo "  void *x = malloc(1);" >> "$OUT_C"
+    echo "  free(x);" >> "$OUT_C"
+    echo "  return 0;" >> "$OUT_C"
+    echo "}" >> "$OUT_C"
     if $LIBTOOL --tag CC --mode link ${CC} ${CPPFLAGS} ${CFLAGS} \
                 -fsanitize=address -fno-omit-frame-pointer \
                 "$OUT_C" ${LIBS} -lasan -o "$OUT"; then