Hi,
I think these problems were caused by the system configuration and other software, not gnupg itself.
Ubuntu 18.04 LTS
Thunderbird 60.7.0
Enigmail 2.0.11
Was installing latest version and ran into errors when doing the 'make check'
Turns out my installation of Ubuntu didn't have the package gnutls-bin installed. I don't know why. I installed it and it fixed the error, but it wasn't an obvious fix based on the error messages.
I included some of the output from 'make check' errors at the end.
After this I was having trouble using my keys. I would receive a message saying 'gpg-agent is older than us.' 'gpgconf --kill all' didn't fix it. I think it was related to the Pretty Easy Privacy and Enigmail plugin for Thunderbird. It seems like PEP did some automatic configuring and key generation that I didn't know about or expect. This might be because I installed the plugin before importing my keys.
I uninstalled the upgrade 'make uninstall'
deleted gpg-agent in usr/local/bin and reinstalled from package manager. (this probably wasn't necessary)
deleted .gpg folder in /home
reinstalled upgrade running 'make clean' first.
Everything works now.
------------------------------------
make check errors
------------------------------------
GnuPG v2.2.15 has been configured as follows:
Revision: dc93e5722 (56467)
Platform: GNU/Linux (x86_64-pc-linux-gnu)
OpenPGP: yes
S/MIME: yes
Agent: yes
Smartcard: yes (without internal CCID driver)
G13: no
Dirmngr: yes
Gpgtar: yes
WKS tools: yes
Protect tool: (default)
LDAP wrapper: (default)
Default agent: (default)
Default pinentry: (default)
Default scdaemon: (default)
Default dirmngr: (default)
Dirmngr auto start: yes
Readline support: yes
LDAP support: no
TLS support: ntbtls
TOFU support: no
Tor support: yes
make check-TESTS
make[2]: Entering directory '/home/en/Downloads/gpg/gnupg-2.2.15/dirmngr'
./t-http-basic: error while loading shared libraries: libntbtls.so.0: cannot open shared object file: No such file or directory
FAIL: t-http-basic
1 of 1 test failed
Please report to https://bugs.gnupg.org
Makefile:1344: recipe for target 'check-TESTS' failed
make[2]: *** [check-TESTS] Error 1
make[2]: Leaving directory '/home/en/Downloads/gpg/gnupg-2.2.15/dirmngr'
Makefile:1467: recipe for target 'check-am' failed
make[1]: *** [check-am] Error 2
make[1]: Leaving directory '/home/en/Downloads/gpg/gnupg-2.2.15/dirmngr'
Makefile:615: recipe for target 'check-recursive' failed
make: *** [check-recursive] Error 1
---------------------------------------------------------------------------------
GPGME v1.13.0 has been configured as follows:
Revision: 1b5a6bf2 (7002)
Platform: x86_64-pc-linux-gnu
UI Server: yes
FD Passing: yes
Language bindings: cl cpp
PASS: initial.test
./t-json: relocation error: ./t-json: symbol gpgrt_strdup version GPG_ERROR_1.0 not defined in file libgpg-error.so.0 with link time reference
FAIL: t-json
stopping gpg-agent
PASS: final.test
1 of 3 tests failed
Please report to https://bugs.gnupg.org
Makefile:609: recipe for target 'check-TESTS' failed
make[4]: *** [check-TESTS] Error 1
make[4]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:732: recipe for target 'check-am' failed
make[3]: *** [check-am] Error 2
make[3]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:734: recipe for target 'check' failed
make[2]: *** [check] Error 2
make[2]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:720: recipe for target 'check-recursive' failed
make[1]: *** [check-recursive] Error 1
make[1]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests'
Makefile:534: recipe for target 'check-recursive' failed
make: *** [check-recursive] Error 1
GPGME v1.13.0 has been configured as follows:
Revision: 1b5a6bf2 (7002)
Platform: x86_64-pc-linux-gnu
UI Server: yes
FD Passing: yes
Language bindings: cl cpp
-------------------------------------------------------
PASS: initial.test
./t-json: relocation error: ./t-json: symbol gpgrt_strdup version GPG_ERROR_1.0 not defined in file libgpg-error.so.0 with link time reference
FAIL: t-json
stopping gpg-agent
PASS: final.test
1 of 3 tests failed
Please report to https://bugs.gnupg.org
Makefile:609: recipe for target 'check-TESTS' failed
make[4]: *** [check-TESTS] Error 1
make[4]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:732: recipe for target 'check-am' failed
make[3]: *** [check-am] Error 2
make[3]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:734: recipe for target 'check' failed
make[2]: *** [check] Error 2
make[2]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests/json'
Makefile:720: recipe for target 'check-recursive' failed
make[1]: *** [check-recursive] Error 1
make[1]: Leaving directory '/home/en/Downloads/gpg/gpgme-1.13.0/tests'
Makefile:534: recipe for target 'check-recursive' failed
make: *** [check-recursive] Error 1