[beast: 6/11] BUILD: generate topbuildid.cc

[Tim Janik <timj src gnome org>]

commit 47d44adbc0d734fef2b38989bfccce6bb3a4679f
Author: Tim Janik <timj gnu org>
Date:   Wed Oct 19 11:52:20 2016 +0200

    BUILD: generate topbuildid.cc
    
    Signed-off-by: Tim Janik <timj gnu org>

 Makefile.am |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 9ec48ba..1ef4fe9 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,8 @@
 # BEAST & BSE
+
+AUTOMAKE_OPTIONS = subdir-objects
 include $(top_srcdir)/Makefile.decl
+topdir = $(abs_top_srcdir)
 
 SUBDIRS = . data sfi bse plugins drivers shell pybeast beast-gtk launchers library tools po tests docs
 
@@ -71,6 +74,14 @@ uninstall_filter_files = $(strip     \
 test_option = test `echo ":$(strip $(1)):" | sed 's/.*:$(strip $(2))://g' | wc -c` -lt \
       `echo ":$(strip $(1)):" | sed 's/.*:$(or $(strip $(3)), no-$(strip $(2)))://g' | wc -c`
 
+# == topbuildid.cc ==
+EXTRA_DIST  += misc/mkbuildid.sh topbuildid.hh
+topbuildid ::= $(shell $(topdir)/misc/mkbuildid.sh -p topbuildid.cc topbuildid.hh) # "update rule" for 
topbuildid.cc
+topbuildid.cc: # avoid explicit deps, 'topbuildid::=' ensures updates
+CLEANFILES += topbuildid.cc    # preserve across 'mostlyclean' if unchanged to avoid expensive rebuilds
+buildid:
+       @echo $(topbuildid)
+
 # == ChangeLog & Release Rules ==
 CHANGELOG_RANGE = $(shell git cat-file -e ce584d04999a7fb9393e1cfedde2048ba73e8878 && \
                    echo ce584d04999a7fb9393e1cfedde2048ba73e8878..HEAD || echo HEAD)