Using gitlog-to-changelog with VPATH builds

[James Youngman]

I just started using gitlog-to-changelog for a project which I
maintain using VPATH builds -- that is, I run "configure" somewhere
other than in $(srcdir).   I found that gitlog-to-changelog didn't
work as well as I had hoped because there is no ./.git.

The gen-ChangeLog rule in coreutils checks for ./.git ...

gen-ChangeLog:
        $(AM_V_GEN)if test -d .git; then                                \
          $(top_srcdir)/build-aux/gitlog-to-changelog                   \
            --amend=$(srcdir)/build-aux/git-log-fix                     \
            --since=$(gen_start_date) > $(distdir)/cl-t;                \
          rm -f $(distdir)/ChangeLog;                                   \
          mv $(distdir)/cl-t $(distdir)/ChangeLog;                      \
        fi

... but for VPATH builds this will likely not exist.   I ended up
using this tweak:

gen-ChangeLog:
        $(AM_V_GEN)if test -d "$(top_srcdir)"/.git; then
         \
          ( cd "$(top_srcdir)" && build-aux/gitlog-to-changelog         \
            --amend=$(srcdir)/build-aux/git-log-fix                     \
            ) >| $(distdir)/cl-t;                                       \
          rm -f $(distdir)/ChangeLog;                                   \
          mv $(distdir)/cl-t $(distdir)/ChangeLog;                      \
        fi

Thanks,
James.