This almost reverts 2761e8a6,
but only if under MINGW32, so it doesn't affect MSVC.

Testing shows that this is closer to what Uniscribe does.

Reported by Khaled Hosny:

"""
commit 56800027
...
This commit is causing a regression with Amiri, the string “هَٰذ” with
Uniscribe and HarfBuzz before this commit, gives:

	[uni0630.fina=3+965|uni0670.medi=0+600|uni064E=0@-256,0+0|uni0647.init=0+926]

But now it gives:

	[uni0630.fina=3+965|uni0670.medi=0+0|uni064E=0@-256,0+0|uni0647.init=0+926]

i.e. uni0670.medi is zeroed though it has a base glyph GDEF class.
"""

The test case is U+0647,U+064E,U+0670,U+0630 with Amiri.

https://bugs.webkit.org/show_bug.cgi?id=113796

We don't use gthread anymore, remove leftovers.

See discussion on mailing list.

After the Ngapi hackfest work, we were assuming that fonts
won't use presentation features to choose specific forms
(eg. conjuncts).  As such, we were using auto-joiner behavior
for such features.  It proved to be troublesome as many fonts
used presentation forms ('pres') for example to form conjuncts,
which need to be disabled when a ZWJ is inserted.

Two examples:

	U+0D2F,U+200D,U+0D4D,U+0D2F with kartika.ttf
	U+0995,U+09CD,U+200D,U+09B7 with vrinda.ttf

What we do now is to never do magic to ZWJ during GSUB's main input
match for Indic-style shapers.  Note that backtrack/lookahead are still
matched liberally, as is GPOS.  This seems to be an acceptable
compromise.

As to the bug that initially started this work, that one needs to
be fixed differently:

  Bug 58714 - Kannada u+0cb0 u+200d u+0ccd u+0c95 u+0cbe does not
  provide same results as Windows8
  https://bugs.freedesktop.org/show_bug.cgi?id=58714

New numbers:

BENGALI: 353689 out of 354188 tests passed. 499 failed (0.140886%)
DEVANAGARI: 707305 out of 707394 tests passed. 89 failed (0.0125814%)
GUJARATI: 366349 out of 366457 tests passed. 108 failed (0.0294714%)
GURMUKHI: 60706 out of 60747 tests passed. 41 failed (0.067493%)
KANNADA: 951030 out of 951913 tests passed. 883 failed (0.0927606%)
KHMER: 299070 out of 299124 tests passed. 54 failed (0.0180527%)
LAO: 53611 out of 53644 tests passed. 33 failed (0.0615167%)
MALAYALAM: 1048102 out of 1048334 tests passed. 232 failed (0.0221304%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271666 out of 271847 tests passed. 181 failed (0.0665816%)
TAMIL: 1091753 out of 1091754 tests passed. 1 failed (9.15957e-05%)
TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%)
TIBETAN: 208469 out of 208469 tests passed. 0 failed (0%)

Ubuntu doesn't (or didn't until recently?) ship icu pkg-config
files.  That's quite unfortunate.  Work around it.

Bug 57608 - ICU Detection fallback for non-pkgconfig systems

That flag is redundant, deprecated, and ignored since April 2011.
From FreeType git log:

commit 8c82ec5b17d0cfc9b0876a2d848acc207a62a25a
Author: Behdad Esfahbod <behdad@behdad.org>
Date:   Thu Apr 21 08:21:37 2011 +0200

    Always ignore global advance.

    This makes FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH redundant,
    deprecated, and ignored.  The new behavior is what every major user
    of FreeType has been requesting.  Global advance is broken in many
    CJK fonts.  Just ignoring it by default makes most sense.

    * src/truetype/ttdriver.c (tt_get_advances),
    src/truetype/ttgload.c (TT_Get_HMetrics, TT_Get_VMetrics,
    tt_get_metrics, compute_glyph_metrics, TT_Load_Glyph),
    src/truetype/ttgload.h: Implement it.

    * docs/CHANGES: Updated.

I added these because the older mingw32 toolchain didn't have
MemoryBarrier().  The newer mingw-w64 toolchain however has.
As reported by John Emmas this was causing build failure with
MSVC (on glib) because of inline issues.  But that reminded me
that we may be taking this path even if the system implements
MemoryBarrier as a function, which is a waste.  So, just remove
it.

Newer automake / libtools warns otherwise.

The fallback happens in higher level already.  No need to do here.

See comments, and this thread:

http://lists.freedesktop.org/archives/harfbuzz/2013-March/002990.html

Originally reported here:

https://code.google.com/p/chromium/issues/detail?id=96143

Doesn't change test suite numbers.

Notifications sent to IRC channel and mailing list.

    Move reusable list of files into variable definitions modules can
    reuse

The overridden "or" operator was preventing the flag expression from
being const, and putting the table in .data instead or .rodata.

Using a ragel machine.

Using a ragel machine.