v1.8.6 build fixes

• python: Fix broken python interface problem(#128), reported by @fd00.
• build: Introduce VPATH build support(#56), suggested by @tkelman.

v1.8.5 security update

• Security fix for CVE-2019-20205 (#127), integer overflow problem,
  reported by @sleicasper.

• Security fix for CVE-2019-20056 (#126), assertion failure problem,
  reported by @sleicasper.

• Security fix for CVE-2019-20094 (#125), heap overflow problem,
  reported by @cuanduo.

• Security fix for #124, illegal longjump() call problem,
  reported by @cuanduo.

• Serucity fix for #74 and #123, access violation problem,
  reported by @hongxuchen and SuhwanSong.

• Security fix for #122, heap overflow problem,
  reported by @SuhwanSong.

• Security fix for CVE-2019-20023(#117, #119, #120), memory leaks problem,
  reported by @SuhwanSong and @gutiniao.

• Strip first flag check in LZW compression function for issue #118,
  reported by @yoichi

For more details, see below summary of vulnerabilities.

No.	assigned CVE	PR	patch	status	fixed on	comment
#67	CVE-2018-14072 CVE-2018-14073	-	f94bc6f 84ed0bc	resolved	v1.8.2
#68	-	-	6a19d99 94a647c	resolved	v1.8.2
#69	-	-	0d70e04	resolved	v1.8.2
#70	-	-	438188c	resolved	v1.8.2
#71	-	-	01c0bad ba21bb9	resolved	v1.8.2
#72	-	-	570d6ae	released	v1.8.3
#73	-	-	cb373ab 26ac06f	resolved	v1.8.4
#74	-	-	0b1e0b3	resolved	v1.8.5
#75	-	-	7808a06	resolved	v1.8.3
#76	-	-	e3a4c0e 3c071b9 d7b2600 197d025	partially resolved	partially fixed on v1.8.3
#77	CVE-2018-19759	#98	5f64fb1	resolved	v1.8.3
#78	CVE-2018-19761	(#106)	(1377517)	resolved	v1.8.3	*same as #105
#79	CVE-2018-19757	#91 #94	e903c93 a53c872	resolved	v1.8.3
#80	CVE-2018-19756	#93	d6e34fc	resolved	v1.8.3
#81	CVE-2018-19762	#92	9861272	resolved	v1.8.3
#82	CVE-2018-19763	#95	614e761	resolved	v1.8.3
#83	CVE-2019-3573 CVE-2019-3574	#99	9c013f2 68ecbc1	resolved	v1.8.3
#85	CVE-2019-11024	-	b418f35	resolved	v1.8.4
#88	-	-	7808a06	resolved	v1.8.3
#89	-	-	a516125	resolved	v1.8.4
#90	-	-	(1377517)	resolved	v1.8.3	*same as #105
#97	-	-	(1377517)	resolved	v1.8.3	*same as #105
#102	CVE-2019-19638	#106	e17c076	resolved	v1.8.3
#103	CVE-2019-19635	#106	1377517	resolved	v1.8.3
#104	CVE-2019-19636	#106	bf46a7b	resolved	v1.8.3
#105	CVE-2019-19637	#106	1377517	resolved	v1.8.3
#107	-	-	1d35033	resolved	v1.8.4
#108	(CVE-2019-19638)	(#106)	(e17c076)	resolved	v1.8.3	*same as #102
#109	CVE-2019-19777	(#93)	(d6e34fc)	resolved	v1.8.3	*same as #80
#110	CVE-2019-19778	(#95)	(614e761)	resolved	v1.8.3	*same as #82
#111	-	(#106)	(1377517)	resolved	v1.8.3	*same as #105
#113	-	(#93)	(aac1df6)	resolved	v1.8.3	*same as #80
#114	-	-	(9d0a7ff)	resolved	v1.8.4	*same as #116
#116	-	-	9d0a7ff	resolved	v1.8.4
#117	CVE-2019-20023	-	b9a4175	resolved	v1.8.5
#118	-	-	6367d2f	resolved	v1.8.4
#119	(CVE-2019-20023)	-	b9a4175	resolved	1.8.5	*same as #117
#120	(CVE-2019-20023)	-	b9a4175	resolved	1.8.5	*same as #117
#121	-		(6367d2f)	resolved	v1.8.4	*same as #118
#122	-		598c8c8	resolved	v1.8.5
#123	-		(0b1e0b3)	resolved	v1.8.5	*same as #74
#124	-		c1ef812	resolved	v1.8.5
#125	CVE-2019-20094		a18b378	resolved	v1.8.5
#126	CVE-2019-20096		814f831	resolved	v1.8.5
#127	CVE-2019-20095		5543354	resolved	v1.8.5

v1.8.4 security update

• Security fix for CVE-2019-11024 (#85), recursive loop problem,
  reported by @Loginsoft-Research.

• Security fix for #73, illegal memory access problem,
  reported by @hongxuchen.

• Security fix for #89, core dumped issue,
  reported by @niugx.

• Security fix for #107, large memory allocation problem,
  reported by @cuanduo.

• Security fix for #114, heap-buffer-overflow problem,
  reported by @SuhwanSong.

• Security fix for #116, heap-buffer-overflow problem,
  reported by @SuhwanSong.

• Security fix for #118, heap-buffer-overflow problem,
  reported by @SuhwanSong.

• Security fix for #121, heap-buffer-overflow problem,
  reported by @gutiniao

For more details, see below summary of vulnerabilities.

No.	assigned CVE	PR	patch	status	fixed on	comment
#67	CVE-2018-14072 CVE-2018-14073	-	f94bc6f 84ed0bc	resolved	v1.8.2
#68	-	-	6a19d99 94a647c	resolved	v1.8.2
#69	-	-	0d70e04	resolved	v1.8.2
#70	-	-	438188c	resolved	v1.8.2
#71	-	-	01c0bad ba21bb9	resolved	v1.8.2
#72	-	-	570d6ae	released	v1.8.3
#73	-	-	cb373ab 26ac06f	resolved	v1.8.4
#74	-	-	-	not resolved	-
#75	-	-	7808a06	resolved	v1.8.3
#76	-	-	e3a4c0e 3c071b9 d7b2600 197d025	partially resolved	partially fixed on v1.8.3
#77	CVE-2018-19759	#98	5f64fb1	resolved	v1.8.3
#78	CVE-2018-19761	(#106)	(1377517)	resolved	v1.8.3	*same as #105
#79	CVE-2018-19757	#91 #94	e903c93 a53c872	resolved	v1.8.3
#80	CVE-2018-19756	#93	d6e34fc	resolved	v1.8.3
#81	CVE-2018-19762	#92	9861272	resolved	v1.8.3
#82	CVE-2018-19763	#95	614e761	resolved	v1.8.3
#83	CVE-2019-3573 CVE-2019-3574	#99	9c013f2 68ecbc1	resolved	v1.8.3
#85	CVE-2019-11024	-	b418f35	resolved	v1.8.4
#88	-	-	7808a06	resolved	v1.8.3
#89	-	-	a516125	resolved	v1.8.4
#90	-	-	(1377517)	resolved	v1.8.3	*same as #105
#97	-	-	(1377517)	resolved	v1.8.3	*same as #105
#102	CVE-2019-19638	#106	e17c076	resolved	v1.8.3
#103	CVE-2019-19635	#106	1377517	resolved	v1.8.3
#104	CVE-2019-19636	#106	bf46a7b	resolved	v1.8.3
#105	CVE-2019-19637	#106	1377517	resolved	v1.8.3
#107	-	-	1d35033	resolved	v1.8.4
#108	(CVE-2019-19638)	(#106)	(e17c076)	resolved	v1.8.3	*same as #102
#109	CVE-2019-19777	(#93)	(d6e34fc)	resolved	v1.8.3	*same as #80
#110	CVE-2019-19778	(#95)	(614e761)	resolved	v1.8.3	*same as #82
#111	-	(#106)	(1377517)	resolved	v1.8.3	*same as #105
#113	-	(#93)	(aac1df6)	resolved	v1.8.3	*same as #80
#114	-	-	(9d0a7ff)	resolved	v1.8.4	*same as #116
#116	-	-	9d0a7ff	resolved	v1.8.4
#117	-	-	b9a4175	patched	-
#118	-	-	6367d2f	resolved	v1.8.4
#119	-	-	b9a4175	patched	-	*same as #117
#120	-	-	b9a4175	patched	-	*same as #117
#121	-		(6367d2f)	resolved	v1.8.4	*same as

Security fix release

• Security fix for CVE-2018-19757 (#79), NULL pointer dereference problem,
  reported by @nluedtke and fixed by @knok (#91, #94).

• Security fix for CVE-2018-19762 (#81), heap-based buffer overflow problem,
  reported by @nluedtke and fixed by @knok (#92).

• Security fix for CVE-2018-19756 (#80), heap-based buffer over-read problem,
  reported by @nluedtke and fixed by @knok (#93).

• Security fix for CVE-2018-19763 (#82, reported by @nluedtke) and CVE-2019-19778 (#110, reported by @SuhwanSong),
  heap-based buffer over-read problem, fixed by @knok (#95).

• Security fix for CVE-2018-19761, illegal address access, fixed by @knok (#96).

• Security fix for CVE-2018-19759, heap-based buffer over-read problem, fixed by @knok (#98).

• Security fix for CVE-2019-3753 (#83), infinite loop problem,
  reported by @cool-tomato and fixed by @knok (#99).

• Security fix for CVE-2018-19759 (#102),
  heap-based buffer over-read that will cause a denial of service.
  reported and fixed by @YourButterfly. (#106)

• Security fix for CVE-2019-19635 (#103), heap-based buffer overflow,
  reported and fixed by @YourButterfly. (#106)

• Security fix for CVE-2019-19636 (#104) and CVE-2019-19637 (#105), integer overflow problem.
  reported and fixed by @YourButterfly. (#106)

• gif loader: check LZW code size (Issue #75), Thanks to @hongxuchen.
  7808a06

• core: Fix a global-buffer-overflow problem (Issue #72), Thanks to @fgeek.
  c868b59

• core: Fix unexpected hangs/performance issues (Issue #76), Thanks to @hongxuchen.
  88561b7
  2d3d9ff
  c9363cd

v1.8.2

This release provides some security updates.

• core: Fix memory leak problems(#67, CVE-2018-14072, CVE-2018-14073), thanks to @fCorleone.
  f94bc6f
  84ed0bc

• core: Fix some heap buffer-overflow problems(#68, #69, #70, #71), thanks to @fgeek.
  6a19d99
  0d70e04
  438188c
  ba21bb9

• man: Fix a typo (#66), thanks to @tsutsui.
  cf47281

libsixel-1.8.1 Bug-fix release

v1.8.1 includes an important bug fix.
600f122

libsixel-1.8 released

              ------------------------------
               What's new in libsixel-1.8 ?
              ------------------------------

• core: Upgrade stb_image to 2.19.

• core: Introduce new dithering method, a_dither / x_dither (http://pippin.gimp.org/a_dither/).
  Thanks to @hodefoting.
  #53

• core: Fix wrong HLS color handling.
  0fb35d2

• core: Improve quality of 15bpp(hi-color mode) dither.
  42f3428

• img2sixel: Allow a deferred clear code in a GIF format
  GIF decoder must do nothing when the table is full.
  See Section "DEFERRED CLEAR CODE IN LZW COMPRESSION" in
  https://www.w3.org/Graphics/GIF/spec-gif89a.txt.
  Thanks to @mame.
  #63

• img2sixel: Marks -D option (read source images from stdin continuously) as deprecated
  9c8ffa6

• Some bug fixes and minor improvements.
  Thanks to @set135, @ttdoda.

• Announcement for package maintainers:
  Immutable tarball is provided, because GitHub auto-generated tarball may be not immutable.

  https://github.com/saitoha/libsixel/releases/download/v1.8.0/libsixel-1.8.0.tar.gz

  For details, see #64 .

v1.7.3

We additionally provide immutable tarball:
https://github.com/saitoha/libsixel/releases/download/v1.7.3/libsixel-1.7.3.tar.gz

According to Issue #64, GitHub auto-generated tarball(https://github.com/saitoha/libsixel/archive/v1.7.3.tar.gz) may be not immutable.