build: pass filenames to check.sh

This ensures in `make check` that $(unstable_protocols) is not
broken.

.build.yml

@@ -6,4 +6,4 @@ sources:
 tasks:
   - protocols: |
       cd wlr-protocols
-      ./check.sh
+      make check

Makefile

@@ -10,8 +10,8 @@ unstable_protocols = \
 	unstable/wlr-output-power-management-unstable-v1.xml \
 	unstable/wlr-screencopy-unstable-v1.xml
 
-check:
-	./check.sh
+check: $(unstable_protocols)
+	./check.sh $(unstable_protocols)
 
 clean:
 	rm -f wlr-protocols.pc

check.sh

@@ -1,7 +1,8 @@
-#!/bin/sh -eux
+#!/bin/sh -eu
 
-for f in $(echo unstable/*.xml)
+for f in "$@"
 do
+	echo >&2 "Checking $f"
 	wayland-scanner -s client-header "$f" /dev/null
 	wayland-scanner -s server-header "$f" /dev/null
 	wayland-scanner -s public-code "$f" /dev/null