[gnome-chess] Fix check for appdata- and desktop-file-validate

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 95fb81ca021abfb281ed88f56d04f32b006a36ad
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Thu Oct 31 14:33:39 2013 -0500

    Fix check for appdata- and desktop-file-validate
    
    If these programs are not installed, do not try to use them. They're
    certainly nice for catching errors, but a developer who wants to use
    these tools will surely have them installed.

 configure.ac     |    3 +++
 data/Makefile.am |    4 ++++
 2 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 53209bd..3e7e73f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -34,7 +34,10 @@ PKG_CHECK_MODULES(TEST, [
 ])
 
 AC_PATH_PROG(APPDATA_VALIDATE, appdata-validate)
+AM_CONDITIONAL([VALIDATE_APPDATA], [test -n "${APPDATA_VALIDATE}"])
+
 AC_PATH_PROG(DESKTOP_FILE_VALIDATE, desktop-file-validate)
+AM_CONDITIONAL([VALIDATE_DESKTOP_FILE], [test -n "${DESKTOP_FILE_VALIDATE}"])
 
 dnl ###########################################################################
 dnl Internationalization
diff --git a/data/Makefile.am b/data/Makefile.am
index 3d3e18a..6c85964 100644
--- a/data/Makefile.am
+++ b/data/Makefile.am
@@ -25,8 +25,12 @@ dist_sysconf_DATA = chess-engines.conf
 dist_man_MANS = gnome-chess.6
 
 check-local: $(appdata_DATA) $(desktop_DATA)
+if VALIDATE_APPDATA
        $(APPDATA_VALIDATE) $(appdata_DATA)
+endif
+if VALIDATE_DESKTOP_FILE
        $(DESKTOP_FILE_VALIDATE) $(desktop_DATA)
+endif
 
 EXTRA_DIST = \
        $(appdata_in_files) \