PGXS is preventing out-of-tree builds of control files

[strk]

The pgxs.mk has, in the install target, this block:

ifneq (,$(EXTENSION))
        $(INSTALL_DATA) $(addprefix $(srcdir)/, $(addsuffix .control, $(EXTENSION))) '$(DESTDIR)$(datadir)/extension/'
endif # EXTENSION

The code is basically prepending $(srcdir) to the .control file path and trying to install it, when EXTENSION variable is set.

In PostGIS we are generating the control files from the control.in files, so when building out-of-source-tree we have those files in the *build* directory, not the *source* directory.

I'd drop PGXS use completely to fix this issue, or at least we'd need to override the install rule

[strk]

I've fixed this, in address_standardizer, by overriding the "install" rule in [9409617baf8997c886e4b52d7f59317ce5d48402/git] Eventually I'd like to drop PGXS as a whole.