[devhelp] docs: do not ignore dh-enum-types.h

[Sébastien Wilmet <swilmet src gnome org>]

commit 3db4bd75710c2b8d648f09ac20859e739290007d
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed May 3 18:05:13 2017 +0200

    docs: do not ignore dh-enum-types.h
    
    This permits to have this in the Object Hierarchy:
    
        GEnum
        ╰── DhLinkType
    
        GFlags
        ╰── DhLinkFlags

 docs/reference/Makefile.am |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/docs/reference/Makefile.am b/docs/reference/Makefile.am
index 17a5550..8c28221 100644
--- a/docs/reference/Makefile.am
+++ b/docs/reference/Makefile.am
@@ -39,15 +39,15 @@ HFILE_GLOB = $(top_srcdir)/src/*.h
 CFILE_GLOB = $(top_srcdir)/src/*.c
 
 # Extra header to include when scanning, which are not under DOC_SOURCE_DIR
-# e.g. EXTRA_HFILES=$(top_srcdir}/contrib/extra.h
-EXTRA_HFILES =
+# e.g. EXTRA_HFILES=$(top_srcdir)/contrib/extra.h
+EXTRA_HFILES = \
+       $(top_builddir)/src/dh-enum-types.h
 
 # Header files or dirs to ignore when scanning. Use base file/dir names
 # e.g. IGNORE_HFILES=gtkdebug.h gtkintl.h private_code
 IGNORE_HFILES = \
        dh-app.h \
        dh-assistant.h \
-       dh-enum-types.h \
        dh-enum-types-app.h \
        dh-error.h \
        dh-parser.h \