[beast: 16/17] DOCS: avoid creation of doc_sources.lst files during make clean or uninstall

[Tim Janik <timj src gnome org>]

commit 8a55d5a3188b1ef5e1e1379a0b29af043d9aa2d1
Author: Tim Janik <timj gnu org>
Date:   Thu Mar 23 16:55:54 2017 +0100

    DOCS: avoid creation of doc_sources.lst files during make clean or uninstall
    
    Signed-off-by: Tim Janik <timj gnu org>

 docs/Makefile.am |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)
---
diff --git a/docs/Makefile.am b/docs/Makefile.am
index bdb167b..2343ecc 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -5,6 +5,7 @@ SUBDIRS = images
 
 MOSTLYCLEANFILES =
 man1_MANS =
+man1_HTMLS =
 man5_MANS =
 man5_HTMLS =
 
@@ -15,14 +16,16 @@ topbuildid ::= $(shell $(topdir)/misc/mkbuildid.sh -p)
 # == Extra Tarball Files ==
 EXTRA_DIST += bse-categories.txt interpolation.txt ChangeLog.svn
 
-# == Collect Doc Sources ==
-sfi_doc_sources          ::= $(shell make doc_sources.lst -C ../sfi >&2 && cat ../sfi/doc_sources.lst)
-bse_doc_sources          ::= $(shell make doc_sources.lst -C ../bse >&2 && cat ../bse/doc_sources.lst)
-plugs_doc_sources ::= $(shell make doc_sources.lst -C ../plugins >&2 && cat ../plugins/doc_sources.lst)
-gxk_doc_sources          ::= $(shell make doc_sources.lst -C ../beast-gtk/gxk >&2 && cat 
../beast-gtk/gxk/doc_sources.lst)
-bst_doc_sources          ::= $(shell make doc_sources.lst -C ../beast-gtk >&2 && cat 
../beast-gtk/doc_sources.lst)
-tools_doc_sources ::= $(shell make doc_sources.lst -C ../tools >&2 && cat ../tools/doc_sources.lst)
-man1_HTMLS          =
+# == Collect Doxygen Sources ==
+# The following variable definitions create files as a side effect, which should be
+# avoided e.g. upon 'make clean'. So we confine the assignments to a rule execution.
+collect_docs_doxy_sources:
+       $(eval sfi_doc_sources   ::= $(shell make doc_sources.lst -C ../sfi >&2 && cat 
../sfi/doc_sources.lst) )
+       $(eval bse_doc_sources   ::= $(shell make doc_sources.lst -C ../bse >&2 && cat 
../bse/doc_sources.lst) )
+       $(eval plugs_doc_sources ::= $(shell make doc_sources.lst -C ../plugins >&2 && cat 
../plugins/doc_sources.lst) )
+       $(eval gxk_doc_sources   ::= $(shell make doc_sources.lst -C ../beast-gtk/gxk >&2 && cat 
../beast-gtk/gxk/doc_sources.lst) )
+       $(eval bst_doc_sources   ::= $(shell make doc_sources.lst -C ../beast-gtk >&2 && cat 
../beast-gtk/doc_sources.lst) )
+       $(eval tools_doc_sources ::= $(shell make doc_sources.lst -C ../tools >&2 && cat 
../tools/doc_sources.lst) )
 
 # == Configure docs ==
 docs_project_link   = http://beast.testbit.eu
@@ -46,7 +49,7 @@ EXTRA_DIST       += $(patsubst %, ../%, $(docs_doxy_extra))
 DOXYGEN_GRAPHICS  ?= NO # YES
 
 # == docs/srctree ==
-doxy/src: $(patsubst %, ../%, $(docs_doxy_sources) $(docs_doxy_extra) $(docs_doxygen_tagbzs))
+doxy/src: $(patsubst %, ../%, $(docs_doxy_sources) $(docs_doxy_extra) $(docs_doxygen_tagbzs)) | 
collect_docs_doxy_sources
        $(AM_V_GEN)
        $(Q) rm -Rf doxy/src doxy/src.tmp
        $(Q) mkdir -p $(docs_doxy_src_dirs:%=doxy/src.tmp/%)