[vte] build: Try fixing builddir != srcdir build

[Christian Persch <chpe src gnome org>]

commit bc0fe14b8a470a717eb2e44ef110153327abd272
Author: Christian Persch <chpe gnome org>
Date:   Sun Sep 14 09:55:49 2014 +0200

    build: Try fixing builddir != srcdir build

 src/Makefile.am |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index a36ac21..f7082d8 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -278,6 +278,8 @@ vte_ VTE_API_MAJOR_VERSION@_ VTE_API_MINOR_VERSION@_VALAFLAGS = \
        $(AM_VALAFLAGS)
 
 vte_ VTE_API_MAJOR_VERSION@_ VTE_API_MINOR_VERSION@_CPPFLAGS = \
+       -I$(top_builddir) \
+       -I$(top_srcdir) \
        $(AM_CPPFLAGS) \
        $(NULL)