Util.un_op -> Option.default
Fixing bug #3865.
Tests for Searchxxx commands added and modified.
Fix treatment of universe context in typecheck inductive (was added
twice). Thanks to Marc Lasson for spotting this.
About now accepts hypothesis names and goal selector.
Documenting check_record + changing a possibly undefined int into int option.
Tests for #3848 and #3854.
New try on Fixing an evar_map bug revealed by commit 603b66f81 on
unification flags (see also temporary revert in d083200ae5b).
Failing on unbound notation variable in notation level modifiers
+ consequences of this check on the standard library (moved the no-op
in Notation modifiers to what there were supposed to do; these are
anyway local notations, so compatibility is safe - please AS or PL,
amend if needed).
Tentatively starting to use heuristics for evar-evar resolution: first
step, prefer QuestionMark's to other evars, to comply with the
filtering made on VarInstance, GoalEvar and QuestionMark for type
class resolution. Maybe evars to be resolved by type class instances
should eventually be marked with a specific tag.

At least, this solves the current problem with compiling cancel2.v in
LemmaOverloading.
Adapted test file for About.
Changed bullet informations to warning for better display in PG.

Since it displays together with the goal, it is better (for pg and
other interfaces probably) that they are in a different message.
Fix for #3154: use CUnix.sys_command to call native compiler.

Patch by CJ on bugzilla. CUnix.sys_command doesn't rely on a shell, so extra
care with cmd.exe vs sh is no longer required.
Error messages of Searchxxx are coherent with goal selector.

If a goal is given and wrong, exception is raised. If no goal is
given, then goal 1 is tried but no failure if goal 1 does not exist,
just fall back to gloab env.
Getting rid of Exninfo hacks.

Instead of modifying exceptions to wear additional information, we instead use
a dedicated type now. All exception-using functions were modified to support
this new type, in particular Future's fix_exn-s and the tactic monad.

To solve the problem of enriching exceptions at raise time and recover this
data in the try-with handler, we use a global datastructure recording the
given piece of data imperatively that we retrieve in the try-with handler.
We ensure that such instrumented try-with destroy the data so that there
may not be confusion with another exception. To further harden the correction
of this structure, we also check for pointer equality with the last raised
exception.

The global data structure is not thread-safe for now, which is incorrect as
the STM uses threads and enriched exceptions. Yet, we splitted the patch in
two parts, so that we do not introduce dependencies to the Thread library
immediatly. This will allow to revert only the second patch if ever we
switch to OCaml-coded lightweight threads.
Proper thread-safe implementation for Exninfo.

This is the second part of the Exninfo patch. It introduces dependency in
the Thread library in all Coq files.
msg_info now puts infomsg tag in emacs mode.

Fixes the idtac "string" not appearing in proofgeneral because
printined *before* the goal.
Fixing CAMLP4 compilation.
fix bug #2447 in congruence
fix bug #2447 in congruence