(backport from rev. 58204)

Fixes issue #1777530; backported from trunk.

to be orderable to properly represent them.
 (backport from rev. 58122)

 (backport from rev. 58119)

(backport from rev. 58117).

(backport from rev. 58115).

a readonly source.

  to include some information about the build environment.

to get dependencies right.

source encoding.

the fileobj argument has no usable name attribute (e.g. StringIO).

(backported from r57616)

made to the trunk awhile ago I believe.

 (backport from rev. 57389)

library installed both were detected so both modules were enabled.  But the include
path causes the recent BerkeleyDB's db.h file to be included causing the bsddb185
compile to fail.  This disables building bsddb185 when both are present.