Vector-sorting fixes.

It's not safe to call qsort or qsort_r, since they have undefined
behavior if the user-specified predicate is not a total order.
Also, watch out for garbage-collection while sorting vectors.
* admin/merge-gnulib (GNULIB_MODULES): Add vla.
* configure.ac (qsort_r): Remove, as we no longer use qsort-like
functions.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/vla.h, m4/vararrays.m4: New files, copied from gnulib.
* lib/stdlib.in.h, m4/stdlib_h.m4: Sync from gnulib, incorporating:
2014-08-29 qsort_r: new module, for GNU-style qsort_r
The previous two files' changes are boilerplate generated by
admin/merge-gnulib, and should not affect Emacs.
* src/fns.c: Include <vla.h>.
(sort_vector_predicate) [!HAVE_QSORT_R]: Remove.
(sort_vector_compare): Remove, replacing with ....
(inorder, merge_vectors, sort_vector_inplace, sort_vector_copy):
... these new functions.
(sort_vector): Rewrite to use the new functions.
GCPRO locals, since the predicate can invoke the GC.
Since it's in-place return void; caller changed.
(merge): Use 'inorder', for clarity.

Fixes: debbugs:18361

3 files changed, 60 insertions, 1 deletions

diff --git a/lib/gnulib.mk b/lib/gnulib.mk
index 9e9b9ebd6de..5ba7de10d0b 100644
--- a/lib/gnulib.mk
+++ b/lib/gnulib.mk
@@ -21,7 +21,7 @@
 # the same distribution terms as the rest of that program.
 #
 # Generated by gnulib-tool.
-# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=stdarg --avoid=stdbool --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt binary-io byteswap c-ctype c-strcase careadlinkat close-stream count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv update-copyright utimens warnings
+# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=stdarg --avoid=stdbool --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt binary-io byteswap c-ctype c-strcase careadlinkat close-stream count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv update-copyright utimens vla warnings
 
 
 MOSTLYCLEANFILES += core *.stackdump
@@ -1141,6 +1141,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
               -e 's/@''GNULIB_PTSNAME''@/$(GNULIB_PTSNAME)/g' \
               -e 's/@''GNULIB_PTSNAME_R''@/$(GNULIB_PTSNAME_R)/g' \
               -e 's/@''GNULIB_PUTENV''@/$(GNULIB_PUTENV)/g' \
+              -e 's/@''GNULIB_QSORT_R''@/$(GNULIB_QSORT_R)/g' \
               -e 's/@''GNULIB_RANDOM''@/$(GNULIB_RANDOM)/g' \
               -e 's/@''GNULIB_RANDOM_R''@/$(GNULIB_RANDOM_R)/g' \
               -e 's/@''GNULIB_REALLOC_POSIX''@/$(GNULIB_REALLOC_POSIX)/g' \
@@ -1192,6 +1193,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
               -e 's|@''REPLACE_PTSNAME''@|$(REPLACE_PTSNAME)|g' \
               -e 's|@''REPLACE_PTSNAME_R''@|$(REPLACE_PTSNAME_R)|g' \
               -e 's|@''REPLACE_PUTENV''@|$(REPLACE_PUTENV)|g' \
+              -e 's|@''REPLACE_QSORT_R''@|$(REPLACE_QSORT_R)|g' \
               -e 's|@''REPLACE_RANDOM_R''@|$(REPLACE_RANDOM_R)|g' \
               -e 's|@''REPLACE_REALLOC''@|$(REPLACE_REALLOC)|g' \
               -e 's|@''REPLACE_REALPATH''@|$(REPLACE_REALPATH)|g' \
@@ -1798,6 +1800,13 @@ EXTRA_DIST += verify.h
 
 ## end   gnulib module verify
 
+## begin gnulib module vla
+
+
+EXTRA_DIST += vla.h
+
+## end   gnulib module vla
+
 ## begin gnulib module xalloc-oversized
 
 if gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index 46e10dba972..ee643247d85 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -520,6 +520,29 @@ _GL_CXXALIAS_SYS (putenv, int, (char *string));
 _GL_CXXALIASWARN (putenv);
 #endif
 
+#if @GNULIB_QSORT_R@
+# if @REPLACE_QSORT_R@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef qsort_r
+#   define qsort_r rpl_qsort_r
+#  endif
+_GL_FUNCDECL_RPL (qsort_r, void, (void *base, size_t nmemb, size_t size,
+                                  int (*compare) (void const *, void const *,
+                                                  void *),
+                                  void *arg) _GL_ARG_NONNULL ((1, 4)));
+_GL_CXXALIAS_RPL (qsort_r, void, (void *base, size_t nmemb, size_t size,
+                                  int (*compare) (void const *, void const *,
+                                                  void *),
+                                  void *arg));
+# else
+_GL_CXXALIAS_SYS (qsort_r, void, (void *base, size_t nmemb, size_t size,
+                                  int (*compare) (void const *, void const *,
+                                                  void *),
+                                  void *arg));
+# endif
+_GL_CXXALIASWARN (qsort_r);
+#endif
+
 
 #if @GNULIB_RANDOM_R@
 # if !@HAVE_RANDOM_R@
diff --git a/lib/vla.h b/lib/vla.h
new file mode 100644
index 00000000000..05125a7978e
--- /dev/null
+++ b/lib/vla.h
@@ -0,0 +1,27 @@
+/* vla.h - variable length arrays
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+   Written by Paul Eggert.  */
+
+/* A function's argument must point to an array with at least N elements.
+   Example: 'int main (int argc, char *argv[VLA_ELEMS (argc)]);'.  */
+
+#ifdef __STDC_NO_VLA__
+# define VLA_ELEMS(n)
+#else
+# define VLA_ELEMS(n) static n
+#endif