scanner: check for wayland-scanner.pc before using variables

If wayland-scanner.pc can't be found the variables end up being set
irrespectively, leaving the user with odd compiler errors about missing
headers, etc.

diff --git a/wayland-scanner.m4 b/wayland-scanner.m4
index 2b87c5f..4e4222a 100644 (file)
--- a/wayland-scanner.m4
+++ b/wayland-scanner.m4
@@ -1,6 +1,8 @@
 AC_DEFUN([WAYLAND_SCANNER_RULES], [
     PKG_PROG_PKG_CONFIG
 
+    PKG_CHECK_MODULES([WAYLAND_SCANNER], [wayland-scanner])
+
     wayland_scanner=`$PKG_CONFIG --variable=wayland_scanner wayland-scanner`
     AC_SUBST([wayland_scanner])