[vte] build: Add no-exceptions sanity check

[Christian Persch <chpe src gnome org>]

commit ff72577bd7d84c30faca3285d7ed4e7f75194f98
Author: Christian Persch <chpe src gnome org>
Date:   Sun Oct 27 12:23:14 2019 +0100

    build: Add no-exceptions sanity check
    
    Some distributions pass -fexceptions in a way that overrides vte's
    own -fno-exceptions. This is a hard error; fail the build.
    
    See https://gitlab.gnome.org/GNOME/gnome-build-meta/issues/207

 src/vteinternal.hh | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
---
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 9b8caca9..3de98d13 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -18,6 +18,23 @@
 
 #pragma once
 
+/* BEGIN sanity checks */
+
+/* Some distributions pass -fexceptions in a way that overrides vte's
+ * own -fno-exceptions. This is a hard error; fail the build.
+ * See https://gitlab.gnome.org/GNOME/gnome-build-meta/issues/207
+ */
+#ifdef __EXCEPTIONS
+#error You MUST NOT use -fexceptions to build vte! Fix your build; and DO NOT file a bug upstream!
+#endif
+
+/* While we're at it, check -fno-rtti too */
+#ifdef __GXX_RTTI
+#error You MUST NOT use -frtti to build vte! Fix your build system; and DO NOT file a bug upstream!
+#endif
+
+/* END sanity checks */
+
 #include <glib.h>
 
 #include "vtedefines.hh"