Log Message:
guile-pg: Update to 0.49

- 0.49 | 2020-11-13

  - dependency clarified: state range

    Previously, the README file intimated that any Guile 1.4.x and
    later would work w/ Guile-PG.  This has now been clarified to
    state the actual working range (1.4.x to 2.0.x, inclusive).

    We have plans for adding support for 2.2.x (and maybe 3.x) in
    the near to middling future.

    See also file test/OK.

  - Guile "auto-compilation" suppressed

    In all three phases: configuration, build, and test, Guile 2.x
    "auto-compilation" of .scm to .go files is suppressed by setting
    the env var ‘GUILE_AUTO_COMPILE=0’.

    We will do intentional compilation at some point, as soon as we
    figure out how to DTRT.  See project CMOD-PLAY for experiments.