[gjs] build: Warn about old gobject-introspection

[Philip Chimento <pchimento src gnome org>]

commit 1b4b80e2c86d0780039c9df1625c57bf7866860c
Author: Philip Chimento <philip chimento gmail com>
Date:   Thu Feb 16 22:05:11 2017 -0800

    build: Warn about old gobject-introspection
    
    We require gobject-introspection 1.41.4 to build. However, with versions
    less that 1.51.2, not all the tests will pass due to some functions being
    missing from the Regress and GIMarshalling libraries. Don't fail the build
    if this is the case, but emit a warning right before the configure
    summary, where it is likely to get noticed.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778780

 configure.ac |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index fd20516..563791f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -249,6 +249,12 @@ AC_CONFIG_LINKS([
 ])
 AC_OUTPUT
 
+# Warn about conditions that affect runtime
+PKG_CHECK_EXISTS([gobject-introspection-1.0 >= 1.51.2], [], [
+    AC_MSG_WARN([You do not have a new enough version of
+gobject-introspection to run the tests. You can still build GJS, but some
+tests will fail.])])
+
 TEST_MSG=
 AM_COND_IF([XVFB_TESTS], [TEST_MSG="xvfb "])
 AM_COND_IF([DBUS_TESTS], [TEST_MSG="${TEST_MSG}dbus"])