PGXS computes srcdir from VPATH, PostgreSQL proper computes VPATH from
srcdir, and doing both results in an error from make. Conditionalize so
only one of these takes effect.
MAJORVERSION = @PG_MAJORVERSION@
# Support for VPATH builds
+# (PGXS VPATH support is handled separately in pgxs.mk)
+ifndef PGXS
vpath_build = @vpath_build@
abs_top_srcdir = @abs_top_srcdir@
srcdir = $(top_srcdir)/$(subdir)
VPATH = $(srcdir)
endif
+endif # not PGXS
vpathsearch = `for f in $(addsuffix /$(1),$(subst :, ,. $(VPATH))); do test -r $$f && echo $$f && break; done`