[gtk-doc] gtk-doc.make: Generate main sgml file by waiting on mkdb

[Stefan Sauer <stefkost src gnome org>]

commit c08cc78562c59082fc83b55b58747177510b7a70
Author: Jan Alexander Steffens (heftig) <jan steffens gmail com>
Date:   Fri Aug 11 21:06:59 2017 +0200

    gtk-doc.make: Generate main sgml file by waiting on mkdb
    
    The 'empty' test fails on some machines when doing a parallel build, as
    make cannot find tester-docs.xml. Add a rule to ensure make waits for
    gtkdoc-mkdb to generate the file.
    This will also fix first time parallel builds.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786174

 gtk-doc.make       |    3 +++
 tests/gtk-doc.make |    3 +++
 2 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/gtk-doc.make b/gtk-doc.make
index e5777b6..d2a8b33 100644
--- a/gtk-doc.make
+++ b/gtk-doc.make
@@ -152,6 +152,9 @@ sgml-build.stamp: setup-build.stamp $(DOC_MODULE)-decl.txt $(SCANOBJ_FILES) $(HF
 sgml.stamp: sgml-build.stamp
        @true
 
+$(DOC_MAIN_SGML_FILE): sgml-build.stamp
+       @true
+
 xml/gtkdocentities.ent: Makefile
        $(GTK_DOC_V_XML)$(MKDIR_P) $(@D) && ( \
                echo "<!ENTITY package \"$(PACKAGE)\">"; \
diff --git a/tests/gtk-doc.make b/tests/gtk-doc.make
index 808fda4..cb8e164 100644
--- a/tests/gtk-doc.make
+++ b/tests/gtk-doc.make
@@ -141,6 +141,9 @@ sgml-build.stamp: setup-build.stamp $(DOC_MODULE)-decl.txt $(SCANOBJ_FILES) $(HF
 sgml.stamp: sgml-build.stamp
        @true
 
+$(DOC_MAIN_SGML_FILE): sgml-build.stamp
+       @true
+
 xml/gtkdocentities.ent: Makefile
        @$(MKDIR_P) $(@D) && ( \
                echo "<!ENTITY package \"$(PACKAGE)\">"; \