HKPS issue with static build of gnupg 2.0.26: checking whether curl is usable: no

[Kristian Fiskerstrand]

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Dear list,

A Gentoo user has run into an issue[0] with using HKPS from a static
build of GnuPG 2.0.26. I seem to be able to replicate this behavior in
a virtual machine, but my debugging seems to stop around the configure
detection of curl being usable. As seen in the configure output in
[1], curl is detected but determined to not be usable:

checking for curl-config... /usr/bin/curl-config
checking for the version of libcurl... 7.39.0
checking for libcurl >= version 7.10... yes
checking whether libcurl is usable... no
                                    ^^^^^

I see this same behavior in my VM for multiple versions of curl; Using
shared linking everything works, but as soon as I try to use static
linking, curl is reported as unusable and gnupg reverts back to using
curl-shim, not supporting HKPS.

Any ideas as to why libcurl is not reported as usable by gnupg despite
having been built to support static linking?

gpg --keyserver hkps://hkps.pool.sks-keyservers.net
- --keyserver-options verbose,debug --search foo
gpgkeys: HTTP search error 1: unsupported protocol
gpgkeys: curl version = GnuPG curl-shim
..

Some info about curl:

curl-config --version
libcurl 7.40.0

curl-config --static-libs
/usr/lib64/libcurl.a -Wl,-O1 -Wl,--as-needed -lcares -lidn -lssl
- -lcrypto -lssl -lcrypto -llber -lldap -lz

curl-config --protocols # (filtered list)
HTTP
HTTPS
LDAP
LDAPS

curl-config --features
SSL
IPv6
UnixSockets
libz
AsynchDNS
IDN
NTLM
NTLM_WB
TLS-SRP


References:
[0] https://bugs.gentoo.org/show_bug.cgi?id=538852
[1] https://538852.bugs.gentoo.org/attachment.cgi?id=395722

- -- 
- ----------------------------
Kristian Fiskerstrand
Blog: http://blog.sumptuouscapital.com
Twitter: @krifisk
- ----------------------------
Public OpenPGP key 0xE3EDFAE3 at hkp://pool.sks-keyservers.net
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