[PATCH] configure: use pkg-config for gpgme

[Daniel Kahn Gillmor <dkg@fifthhorseman.net>]

GnuPG upstream has supported pkg-config since gpgme version 1.13 and
gpg-error 1.33, and now prefers the use of pkg-config by default,
instead of relying on gpg-error-config and gpgme-config.

As of libgpg-error 1.46, upstream deliberately does not ship
gpg-error-config by default.  As of gpgme 1.18.0, upstream does not
ship gpgme-config if gpg-error-config is also not present.

Both of these versions of upstream libraries are in debian unstable
now.  To the extent that notmuch is dependent on GnuPG, it should
follow GnuPG upstream's lead.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 configure | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index be69b34d..c3629a73 100755
--- a/configure
+++ b/configure
@@ -541,8 +541,8 @@ version of GPGME.
 Please try to rebuild your version of GMime against a more recent
 version of GPGME (at least GPGME 1.8.0).
 EOF
-	if command -v gpgme-config >/dev/null; then
-	    printf 'Your current GPGME development version is: %s\n' "$(gpgme-config --version)"
+	if GPGME_VERS="$(pkg-config --modversion gpgme || gpgme-config --version)"; then
+	    printf 'Your current GPGME development version is: %s\n' "$GPGME_VERS"
 	else
 	    printf 'You do not have the GPGME development libraries installed.\n'
 	fi
-- 
2.35.1