Rewrite merge of clause variable tables (in case, try, etc)

erl_lint:icrt_export/4 has been rewritten to make the code really
follow the scoping rules of Erlang, and not just in most situations
by accident.

 * The function should not depend on calling unused_vars/3 because that
   function does not return variables which begins with an underscore,
   something that only matters when emitting warnings. This could cause
   a compiler crash if such a variable was reused afterwards.

 * The variable tables from each clause are first merged together,
   lists:merge/1 is safe to use because they are orddicts and thus
   already sorted. This list is then traversed parallelly to the old
   variable table, again taking advantage of their sorted order.

 * The function does not emit warnings itself, there is no need to pass
   around the lint state. In the same vein, vtunsafe/3 has been rewritten
   to do more things by itself, given that all of its calls were similar.
   Finally, compiled-out code has been removed.

 * This reverts the code in 9ce148b1059e4da746a11f1d80a653340216c468,
   which fixed the compiler crash and made erl_lint remember unsafe
   variables, but forget about unused variables in the process.

 * Other places of the code which relied on the old clunky behaviour were
   also updated: unused and unsafe old variables are forgotten when
   merging fun clauses and boolean shortcircuiting operators do not rely
   on icrt_export/3 anymore.
Fix HiPE debug lock checking on OS X 64bit

Position-independent code is mandatory on OS X. We use r11 as an intermediate
register to fill BIF_P->hipe.bif_callee. This fixes the following error when
doing `make debug FLAVOR=smp`:

clang -cc1as: fatal error: error in backend: 32-bit absolute addressing is not supported in 64-bit mode
Install internal hrl files when necessary

Sometimes we install *.erl files. Some these files include a private
*.hrl files, so in order to make these *.erl files usable we have to
install these private includes as well.

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
let Java compiler output all warnings
Do not rely on macros with implicit vars

This commit also provides the benefit that the Label argument
in gen:call/3 is no longer used, as we can access the sender
in the From argument. Therefore, we should be able to change
the Label to something more relevant in the future.
stdlib: Fix maps type pretty printing

Properly align union typed assoc values.
Fix broken deprecation warnings in ssh application
edoc, erl_docgen: Enhance internal map type format
Fixed typo: was/were
erts: Fix erts app-file
Next expected version... (may change)
Add note about adjacent separator characters in string:tokens/2

Adjacent separator characters are treated as one in
string:tokens/2. This was shown in the example in the reference manual
but it was not written in words. A note about this is now added.
ssh: Avoid timeout of init_per_test_case on some platforms

Also some code cleanup
[ct] Fix path of cover export/import files

5a3c4668 accidentially changed the base directory for cover export
and import files, if given as relative paths. This commit fixes this -
the files are again expected to be given relative to the directory of
the cover spec file itself, or else as absolute paths.
Add note about known issue with -Wrace_conditions

As noted on the erlang-bugs mailing list:
http://erlang.org/pipermail/erlang-bugs/2014-July/004518.html
ssh: Avoid windows wierdness
Merge branch 'siri/string-tokens-doc/OTP-12036' into maint

* siri/string-tokens-doc/OTP-12036:
  Add note about adjacent separator characters in string:tokens/2
Merge branch 'maint'

Conflicts:
	OTP_VERSION
Merge branch 'siri/ct-cover-import-path/OTP-12031' into maint

* siri/ct-cover-import-path/OTP-12031:
  [ct] Fix path of cover export/import files
Merge branch 'maint'