libksba: update to version 1.6.7

libksba: update to version 1.6.7

Release 1.6.7
 build: Update autogen.sh and make SYSROOT available.
 Allow for an empty Subject in certs.
 Update gpg-error.m4.
 Apply spell fixes from GnuPG.
 m4: Update gpg-error.m4 from gpg-error master.
 ksba.m4: Fix setting/using GPG_ERROR_CONFIG.
 Fix the previous commit.
 m4: Include _AM_PATH_GPGRT_CONFIG definition.
 Use unsigned int for 1-bit flags.
 Post release updates

Release 1.6.6
 der-builder: Fix possible uninitialized variable.
 Post release updates.

Release 1.6.5
 Add Brainpool curve detection using parameters with compressed BP.
 build: Remove HAVE_W32CE_SYSTEM.
 doc: Minor style fixes.
 build: Change the default for --with-libtool-modification.
 build: New configure option --with-libtool-modification.
 Post release updates

Signed-off-by: Daniel Golle <redacted>