3.35.x/3.36.0 test failure on Ubuntu: gcr:gck / attributes: test_build_data_secure: assertion failed: (egg_secure_check (attr->value) == TRUE)

Originally reported by @seb128 on #42 (closed), but I'm separating this one from the slots test failure because it seems to be orthogonal (we don't see it in Debian).

https://launchpadlibrarian.net/468759476/buildlog_ubuntu-focal-amd64.gcr_3.36.0-1_BUILDING.txt.gz

14/43 gcr:gck / attributes                    FAIL     0.18 s (killed by signal 6 SIGABRT)

--- command ---
08:49:39 /<<PKGBUILDDIR>>/obj-x86_64-linux-gnu/gck/test-gck-attributes
--- stdout ---
# random seed: R02Se96270826ac9f9580e2d1f2dfa9c3f51
1..53
# Start of gck tests
# Start of value tests
ok 1 /gck/value/to_boolean
ok 2 /gck/value/to_ulong
# End of value tests
# Start of attribute tests
ok 3 /gck/attribute/init_memory
ok 4 /gck/attribute/init_boolean
ok 5 /gck/attribute/init_date
ok 6 /gck/attribute/init_ulong
ok 7 /gck/attribute/init_string
ok 8 /gck/attribute/init_invalid
ok 9 /gck/attribute/init_empty
ok 10 /gck/attribute/new_memory
ok 11 /gck/attribute/new_boolean
ok 12 /gck/attribute/new_date
ok 13 /gck/attribute/new_ulong
ok 14 /gck/attribute/new_string
ok 15 /gck/attribute/new_invalid
ok 16 /gck/attribute/new_empty
ok 17 /gck/attribute/get_boolean
ok 18 /gck/attribute/get_date
ok 19 /gck/attribute/get_ulong
ok 20 /gck/attribute/get_string
ok 21 /gck/attribute/dup_attribute
ok 22 /gck/attribute/copy_attribute
ok 23 /gck/attribute/hash
# End of attribute tests
# Start of builder tests
ok 24 /gck/builder/blank
ok 25 /gck/builder/data
ok 26 /gck/builder/data-invalid
Bail out! Gck:ERROR:../gck/test-gck-attributes.c:420:test_build_data_secure: assertion failed: (egg_secure_check (attr->value) == TRUE)
--- stderr ---
**
Gck:ERROR:../gck/test-gck-attributes.c:420:test_build_data_secure: assertion failed: (egg_secure_check (attr->value) == TRUE)
-------

https://launchpadlibrarian.net/466383302/buildlog_ubuntu-focal-amd64.gcr_3.35.91-1~build2_BUILDING.txt.gz also had this failure.