libidn: Update to 1.34

libidn: Update to 1.34

For details see:
https://lists.gnu.org/archive/html/info-gnu/2018-04/msg00001.html

"* Version 1.34 (2018-03-31)

** libidn: Fix integer overflow in combine_hangul()
   Found by fuzzing.
** libidn: Fix integer overflow in punycode decoder
   Found by fuzzing, fix for the fix reported by Christian Weisgerber
** libidn: Fix performance issue in idna_to_unicode_internal()
   Found by fuzzing.
** libidn: Fix performance issue in stringprep functions.
   Found by fuzzing.
** libidn: Fix NULL pointer dereference in g_utf8_normalize()
   Found by fuzzing.
** libidn: Fix NULL pointer dereference in stringprep_ucs4_nfkc_normalize()
   Found by fuzzing.
** libidn: Increase performance of stringprep functions
   Found by fuzzing.
** testing: Add OSS-fuzz integration and regression testing
** build: Update gnulib files
** build: Modernize GTK-Doc build
** build: Fix parallel builds
** build: Add configure flag --disable-doc
** build: Add configure flag --enable-ubsan (enable UB Sanitizer)
** build: Add configure flag --enable-asan (enable Address Sanitizer)
** build: Fix compiler warnings
** build: Fix build for gcc-7
** i18n: Added Swedish translation.
   Thanks to Josef Andersson.
** API and ABI is backwards compatible with the previous version."

Best,
Matthias

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>