backend depends on libpgport but Make doesn't know

I think we're missing a dependency declaration from the backend to
libpgport in the makefiles somewhere. I just git updated on 9.1 on a
tree that was already built, ran make, and got this:

../../src/port/libpgport_srv.a(dirmod_srv.o): In function `rmtree':
/pgsql/source/REL9_1_STABLE/src/port/dirmod.c:546: undefined reference to `snprintf_throw_on_fail'
../../src/port/libpgport_srv.a(exec_srv.o): In function `pclose_check':
/pgsql/source/REL9_1_STABLE/src/port/exec.c:535: undefined reference to `snprintf_throw_on_fail'
../../src/port/libpgport_srv.a(exec_srv.o): In function `find_other_exec':
/pgsql/source/REL9_1_STABLE/src/port/exec.c:319: undefined reference to `snprintf_throw_on_fail'
/pgsql/source/REL9_1_STABLE/src/port/exec.c:325: undefined reference to `snprintf_throw_on_fail'
../../src/port/libpgport_srv.a(exec_srv.o): In function `pipe_read_line':
/pgsql/source/REL9_1_STABLE/src/port/exec.c:366: undefined reference to `fprintf_throw_on_fail'
../../src/port/libpgport_srv.a(exec_srv.o): In function `set_pglocale_pgservice':
/pgsql/source/REL9_1_STABLE/src/port/exec.c:609: undefined reference to `snprintf_throw_on_fail'
/pgsql/source/REL9_1_STABLE/src/port/exec.c:598: undefined reference to `snprintf_throw_on_fail'
collect2: error: ld returned 1 exit status
make[2]: *** [postgres] Error 1

The solution is obvious, just "make clean" on src/port -- or
alternatively as Tom says, just clean the build every time before git
pull'ing. But since most cases with --enable-depend actually work fine
without either of those things, it's annoying that this small part
doesn't.

Anybody has a clue how to fix this, so that libpgport is rebuilt when
its files have changed? I guess we would have to have the backend
depend on each individual file on src/port ...?

--
Álvaro Herrera http://www.2ndQuadrant.com/
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