toolchain.eclass: pull virtual/libcrypt as a dependency for USE=sanitize

Closes: https://bugs.gentoo.org/802648
Signed-off-by: Sergei Trofimovich <[email protected]>

eclass/toolchain.eclass

@@ -157,7 +157,7 @@ if [[ ${PN} != "kgcc64" && ${PN} != gcc-* ]] ; then
  tc_version_is_at_least 4.7 && IUSE+=" go"
  # sanitizer support appeared in gcc-4.8, but <gcc-5 does not
  # support modern glibc.
- tc_version_is_at_least 5 && IUSE+=" +sanitize"
+ tc_version_is_at_least 5 && IUSE+=" +sanitize" TC_FEATURES+=(sanitize)
  # Note:
  # <gcc-4.8 supported graphite, it required forked ppl
  # versions which we dropped. Since graphite was also experimental in
@@ -245,6 +245,13 @@ if tc_has_feature gcj ; then
  "
 fi
 
+if tc_has_feature sanitize ; then
+ # libsanitizer relies on 'crypt.h' to be present
+ # on target. glibc user to provide it unconditionally.
+ # Nowadays it's a standalone library: #802648
+ DEPEND+=" sanitize? ( virtual/libcrypt )"
+fi
+
 if tc_has_feature systemtap ; then
  # gcc needs sys/sdt.h headers on target
  DEPEND+=" systemtap? ( dev-util/systemtap )"