Adds trivial_example.c to make dist
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 02f3493..296c4dd 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -9,7 +9,8 @@
             $(top_srcdir)/doc/footer.html \
             $(top_srcdir)/doc/customdoxygen.css
 
-EXTRA_DIST = customdoxygen.css Doxyfile.in footer.html header.html opus_logo.svg
+EXTRA_DIST = customdoxygen.css Doxyfile.in footer.html header.html \
+             opus_logo.svg trivial_example.c
 
 
 if HAVE_DOXYGEN