patch 8.0.1306: ASAN error stack trace is not useful

Problem:    ASAN error stack trace is not useful.
Solution:   Add "asan_symbolize". (James McCoy, closes #2344)

.travis.yml

@@ -67,6 +67,7 @@ addons:
   apt:
     packages:
       - autoconf
+      - clang
       - lcov
       - libperl-dev
       - python-dev
@@ -102,9 +103,8 @@ script:
   - (cd ${SRCDIR} && ./configure --with-features=$FEATURES $CONFOPT --enable-fail-if-missing && if [ "$BUILD" = "yes" ]; then make -j$NPROC; fi)
     # Show Vim version and also if_xx versions.
   - if [ "$BUILD" = "yes" ]; then ${SRCDIR}/vim --version; ${SRCDIR}/vim --not-a-term -u NONE -S ${SRCDIR}/testdir/if_ver-1.vim -c quit > /dev/null; ${SRCDIR}/vim --not-a-term -u NONE -S ${SRCDIR}/testdir/if_ver-2.vim -c quit > /dev/null; cat if_ver.txt; fi
-  - if [ -n "$ASAN_OPTIONS" ]; then export PATH=/usr/lib/llvm-$(clang -v 2>&1 | sed -n 's/.*version \([1-9]\.[0-9][0-9]*\).*/\1/p')/bin:$PATH; fi
   - make $SHADOWOPT $TEST
-  - if [ -n "$ASAN_OPTIONS" ]; then for log in $(find -type f -name 'asan.*' -size +0); do cat "$log"; err=1; done; fi
+  - if [ -n "$ASAN_OPTIONS" ]; then for log in $(find -type f -name 'asan.*' -size +0); do asan_symbolize < "$log"; err=1; done; fi
   - if [ -n "$err" ]; then exit 1; fi
 
 after_success:

src/version.c

@@ -766,6 +766,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1306,
 /**/
     1305,
 /**/