meson: better error for wcap dep cairo

Add human-friendly error message.

Cairo is a hard dependency on the whole at least because tests seem to
require it, but this will help if someone adds an option to disable
building tests to get rid of Cairo.

Signed-off-by: Pekka Paalanen <pq@iki.fi>

diff --git a/wcap/meson.build b/wcap/meson.build
index 9a47cdb524edf60f9cf59fcdba550ae56009543d..02281c98d86bb502aea1907ba38b25dc991f8c58 100644 (file)
--- a/wcap/meson.build
+++ b/wcap/meson.build
@@ -7,15 +7,15 @@ srcs_wcap = [
        'wcap-decode.c',
 ]
 
-deps_wcap = [
-       dep_libm,
-       dependency('cairo'),
-]
+wcap_dep_cairo = dependency('cairo', required: false)
+if not wcap_dep_cairo.found()
+       error('wcap requires cairo which was not found. Or, you can use \'-Dwcap-decode=false\'.')
+endif
 
 executable(
        'wcap-decode',
        srcs_wcap,
        include_directories: include_directories('..'),
-       dependencies: deps_wcap,
+       dependencies: [ dep_libm, wcap_dep_cairo ],
        install: true
 )