an experiment: clearing the C stack in gc tests

* test-suite/lib.scm (clear-stale-stack-references): New helper.
* test-suite/tests/gc.test:
* test-suite/tests/threads.test: Use the new helper.

I removed the "unresolved" throw, as I'd like to see what the bots do
with this.
Augment `Libs.private' in `guile-2.0-uninstalled.pc'.

Followup to 58f86505d658359508732c8f187bc37d010074d0 ("Augment
`Libs.private' with for non-GNU platforms.").

Reported by Eli Zaretskii <eliz@gnu.org>.

* meta/guile-2.0-uninstalled.pc.in (Libs): Add all the optional
  libraries, as done in commit 58f86505d658359508732c8f187bc37d010074d0.
leniency in the "unused modules are removed" gc.test

* libguile/foreign.h: Remove comment about the finalizer bit, as I don't
  think that is the case any more.

* test-suite/tests/gc.test: Ignore flakiness in the gc-modules test.
Fix search_path to fill stat_buf when given an absolute pathname

* libguile/load.c (search_path): When the provided 'filename' is an
  absolute pathname, perform a 'stat' on that pathname to fill the
  'stat_buf'.  Previously, 'stat_buf' was left uninitialized in this
  case, even though 'scm_primitive_load_path' assumes that 'stat_buf'
  will be filled.  Update the header comment to explicitly specify that
  'stat_buf' will be filled.  Also 'goto end' in a few failure cases
  instead of replicating its code.
Update srfi-14 character sets to Unicode 6.1

* libguile/srfi-14.i.c (cs_lower_case_ranges, cs_lower_case)
  (cs_upper_case_ranges, cs_upper_case, cs_letter_ranges, cs_letter)
  (cs_digit_ranges, cs_digit, cs_letter_plus_digit_ranges, cs_letter_plus_digit)
  (cs_graphic_ranges, cs_graphic, cs_printing_ranges, cs_printing)
  (cs_punctuation_ranges, cs_punctuation, cs_symbol_ranges, cs_symbol)
  (cs_designated_ranges, cs_designated): modified
* doc/ref/api-data.texi: modified
Fix unbalanced parentheses in docs.

* doc/ref/sxml-match.texi (sxml-match-let, sxml-match-let*): Remove
  extraneous parenthesis at end of Texinfo function definition header.
Make consistent the usage of variable names in the function definitions found in the Texinfo docs.

* doc/r5rs/r5rs.texi:
* doc/ref/api-compound.texi:
* doc/ref/api-data.texi:
* doc/ref/api-debug.texi:
* doc/ref/api-evaluation.texi:
* doc/ref/api-io.texi:
* doc/ref/api-modules.texi:
* doc/ref/api-procedures.texi:
* doc/ref/api-scheduling.texi:
* doc/ref/api-smobs.texi:
* doc/ref/compiler.texi:
* doc/ref/misc-modules.texi:
* doc/ref/posix.texi:
* doc/ref/scheme-using.texi:
* doc/ref/srfi-modules.texi:
* doc/ref/vm.texi:
* doc/ref/web.texi:
* doc/sources/env.texi: Make usage of variable names of function definitions
  more consistent.
Remove unused doc/sources/

* doc/sources: Remove.  It is not used at all, presumably because all it
  had to offer was already incorporated in the manual.
Improve the usage of variable names in C docstrings.

* libguile/alist.c:
* libguile/array-map.c:
* libguile/arrays.c:
* libguile/bitvectors.c:
* libguile/filesys.c:
* libguile/foreign.c:
* libguile/generalized-arrays.c:
* libguile/hashtab.c:
* libguile/ioext.c:
* libguile/load.c:
* libguile/numbers.c:
* libguile/ports.c:
* libguile/posix.c:
* libguile/print.c:
* libguile/procprop.c:
* libguile/promises.c:
* libguile/simpos.c:
* libguile/socket.c:
* libguile/srfi-1.c:
* libguile/srfi-13.c:
* libguile/srfi-14.c:
* libguile/stacks.c:
* libguile/stime.c:
* libguile/strings.c:
* libguile/struct.c:
* libguile/symbols.c:
* libguile/threads.c:
* libguile/weak-table.c:
* libguile/weak-vector.c: Make the variable names in the C docstrings more
  consistent.  Replace a few instances of @var with @code when appropriate.
Improve the usage of variable names in Scheme docstrings.

* module/ice-9/boot-9.scm:
* module/ice-9/popen.scm:
* module/ice-9/pretty-print.scm:
* module/ice-9/r4rs.scm:
* module/rnrs/io/ports.scm:
* module/texinfo/string-utils.scm:
* module/web/http.scm:
* module/web/request.scm:
* module/web/response.scm:
* test-suite/vm/run-vm-tests.scm: Make the variable names in Scheme docstrings more
  consistent.  Replace a few instances of @var with @code when appropriate.
Fix case in identifiers starting sentences in doc/r5rs/r5rs.texi

* doc/r5rs/r5rs.texi: Use proper case of characters in identifiers starting
  sentences.
Fix `SCM_I_ERROR' definition for MinGW without networking.

* libguile/error.c (SCM_I_ERROR)[__MINGW32__]: Conditionalize on
  `HAVE_NETWORKING'.
revert r5rs changes

* doc/r5rs/r5rs.texi: Reverts the recent changes to r5rs.texi.
Implement scm_to_pointer

* libguile/foreign.c, libguile/foreign.h (scm_to_pointer):
  New C function.

* test-suite/standalone/test-loose-ends.c: Add test.
Update srfi-14 test for Unicode 6.1

Some Latin-1 symbols have been reclassified as punctuation

* test-suite/tests/srfi-14.test: updated
tests: Work around erroneous tr_TR locale in Darwin 8.

* test-suite/tests/i18n.test (under-turkish-utf8-locale-or-unresolved):
  Add exception for Darwin 8.  Reported by David Fang <fang@csl.cornell.edu>,
  see <http://bugs.gnu.org/10684>.
tests: Have `getaddrinfo' test work for Darwin 8.

* doc/ref/posix.texi (Network Databases): Update description of
  `EAI_NODATA' to mention that Darwin provides it.

* libguile/net_db.c (scm_getaddrinfo): Likewise.

* test-suite/tests/net-db.test ("getaddrinfo")["wrong service name"]:
  Accept `EAI_NODATA' too.  Reported by David Fang <fang@csl.cornell.edu>,
  see <http://bugs.gnu.org/10684>.
Use Gnulib's `regex' module.

This should help with regex portability, as reported in
<http://bugs.gnu.org/10684> for Darwin 8.11.

* m4/gnulib-cache.m4 (gl_MODULES): Add `regex'.

* configure.ac: Remove header checks for regex.h, rxposix.h, and
  rx/rxposix.h.  Remove check for the `regcomp' function.  Remove
  definition of `HAVE_REGCOMP'.  Define `ENABLE_REGEX'.

* libguile/init.c: Check for `ENABLE_REGEX' instead of `HAVE_REGCOMP'.

* libguile/regex-posix.c: Always include <regex.h>.  Remove #ifdefs for
  rxposix.h and co.
i18n: Use Gnulib's `nl_langinfo' module.

* configure.ac: Remove checks for <langinfo.h> and <nl_types.h>, and
  `nl_langinfo'.

* libguile/i18n.c: Remove #ifdefs for HAVE_LANGINFO_H, HAVE_NL_TYPES_H,
  HAVE_NL_ITEM, and HAVE_LANGINFO_CODESET.
  (SCM_VALIDATE_OPTIONAL_LOCALE_COPY): Use `SCM_UNBNDP'.

* m4/gnulib-cache.m4 (gl_MODULES): Add `nl_langinfo'.

* module/ice-9/i18n.scm (define-vector-langinfo-mapping): Remove
  `defaults' parameter; assume (provided? 'nl-langinfo) is always true.
  Update users accordingly.
  (define-simple-langinfo-mapping): Likewise.
  (define-monetary-langinfo-mapping): Likewise, but do not assume
  LOCAL-ITEM and INTL-ITEM are always defined.
i18n: Add a couple of tests for `monetary-amount->locale-string'.

* test-suite/tests/i18n.test ("monetary-amount->locale-string"): New
  test prefix.