Add `etcpak` library for faster ETC/ETC2/S3TC imports.

- `etc` module was renamed to `etcpak` and modified to use the new library.
- PKM importer is removed in the process, it's obsolete.
- Old library `etc2comp` is removed.
- S3TC compression no longer done via `squish` (but decompression still is).
- Slight modifications to etcpak sources for MinGW compatibility,
  to fix LLVM `-Wc++11-narrowing` errors, and to allow using vendored or
  system libpng.

Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>

1 files changed, 0 insertions, 224 deletions

diff --git a/thirdparty/etc2comp/patches/fix-rgba8-max-channels.patch b/thirdparty/etc2comp/patches/fix-rgba8-max-channels.patch
deleted file mode 100644
index ea9b5640b6..0000000000
--- a/thirdparty/etc2comp/patches/fix-rgba8-max-channels.patch
+++ /dev/null
@@ -1,224 +0,0 @@
-diff --git a/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8.cpp b/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8.cpp
-index 5656556db9..5c7ebed788 100644
---- a/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8.cpp
-+++ b/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8.cpp
-@@ -508,7 +508,7 @@ namespace Etc
- 		int iMaxRed1 = iColor1Red + (int)a_uiRadius;
- 		if (iMaxRed1 > 15)
- 		{
--			iMinRed1 = 15;
-+			iMaxRed1 = 15;
- 		}
- 
- 		int iMinGreen1 = iColor1Green - (int)a_uiRadius;
-@@ -519,7 +519,7 @@ namespace Etc
- 		int iMaxGreen1 = iColor1Green + (int)a_uiRadius;
- 		if (iMaxGreen1 > 15)
- 		{
--			iMinGreen1 = 15;
-+			iMaxGreen1 = 15;
- 		}
- 
- 		int iMinBlue1 = iColor1Blue - (int)a_uiRadius;
-@@ -530,7 +530,7 @@ namespace Etc
- 		int iMaxBlue1 = iColor1Blue + (int)a_uiRadius;
- 		if (iMaxBlue1 > 15)
- 		{
--			iMinBlue1 = 15;
-+			iMaxBlue1 = 15;
- 		}
- 
- 		int iColor2Red = m_frgbaOriginalColor2_TAndH.IntRed(15.0f);
-@@ -545,7 +545,7 @@ namespace Etc
- 		int iMaxRed2 = iColor2Red + (int)a_uiRadius;
- 		if (iMaxRed2 > 15)
- 		{
--			iMinRed2 = 15;
-+			iMaxRed2 = 15;
- 		}
- 
- 		int iMinGreen2 = iColor2Green - (int)a_uiRadius;
-@@ -556,7 +556,7 @@ namespace Etc
- 		int iMaxGreen2 = iColor2Green + (int)a_uiRadius;
- 		if (iMaxGreen2 > 15)
- 		{
--			iMinGreen2 = 15;
-+			iMaxGreen2 = 15;
- 		}
- 
- 		int iMinBlue2 = iColor2Blue - (int)a_uiRadius;
-@@ -567,7 +567,7 @@ namespace Etc
- 		int iMaxBlue2 = iColor2Blue + (int)a_uiRadius;
- 		if (iMaxBlue2 > 15)
- 		{
--			iMinBlue2 = 15;
-+			iMaxBlue2 = 15;
- 		}
- 
- 		for (unsigned int uiDistance = 0; uiDistance < TH_DISTANCES; uiDistance++)
-@@ -761,7 +761,7 @@ namespace Etc
- 		int iMaxRed1 = iColor1Red + (int)a_uiRadius;
- 		if (iMaxRed1 > 15)
- 		{
--			iMinRed1 = 15;
-+			iMaxRed1 = 15;
- 		}
- 
- 		int iMinGreen1 = iColor1Green - (int)a_uiRadius;
-@@ -772,7 +772,7 @@ namespace Etc
- 		int iMaxGreen1 = iColor1Green + (int)a_uiRadius;
- 		if (iMaxGreen1 > 15)
- 		{
--			iMinGreen1 = 15;
-+			iMaxGreen1 = 15;
- 		}
- 
- 		int iMinBlue1 = iColor1Blue - (int)a_uiRadius;
-@@ -783,7 +783,7 @@ namespace Etc
- 		int iMaxBlue1 = iColor1Blue + (int)a_uiRadius;
- 		if (iMaxBlue1 > 15)
- 		{
--			iMinBlue1 = 15;
-+			iMaxBlue1 = 15;
- 		}
- 
- 		int iColor2Red = m_frgbaOriginalColor2_TAndH.IntRed(15.0f);
-@@ -798,7 +798,7 @@ namespace Etc
- 		int iMaxRed2 = iColor2Red + (int)a_uiRadius;
- 		if (iMaxRed2 > 15)
- 		{
--			iMinRed2 = 15;
-+			iMaxRed2 = 15;
- 		}
- 
- 		int iMinGreen2 = iColor2Green - (int)a_uiRadius;
-@@ -809,7 +809,7 @@ namespace Etc
- 		int iMaxGreen2 = iColor2Green + (int)a_uiRadius;
- 		if (iMaxGreen2 > 15)
- 		{
--			iMinGreen2 = 15;
-+			iMaxGreen2 = 15;
- 		}
- 
- 		int iMinBlue2 = iColor2Blue - (int)a_uiRadius;
-@@ -820,7 +820,7 @@ namespace Etc
- 		int iMaxBlue2 = iColor2Blue + (int)a_uiRadius;
- 		if (iMaxBlue2 > 15)
- 		{
--			iMinBlue2 = 15;
-+			iMaxBlue2 = 15;
- 		}
- 
- 		for (unsigned int uiDistance = 0; uiDistance < TH_DISTANCES; uiDistance++)
-diff --git a/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8A1.cpp b/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8A1.cpp
-index ba2b42fb05..b94b64e68c 100644
---- a/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8A1.cpp
-+++ b/thirdparty/etc2comp/EtcBlock4x4Encoding_RGB8A1.cpp
-@@ -847,7 +847,7 @@ namespace Etc
- 		int iMaxRed1 = iColor1Red + (int)a_uiRadius;
- 		if (iMaxRed1 > 15)
- 		{
--			iMinRed1 = 15;
-+			iMaxRed1 = 15;
- 		}
- 
- 		int iMinGreen1 = iColor1Green - (int)a_uiRadius;
-@@ -858,7 +858,7 @@ namespace Etc
- 		int iMaxGreen1 = iColor1Green + (int)a_uiRadius;
- 		if (iMaxGreen1 > 15)
- 		{
--			iMinGreen1 = 15;
-+			iMaxGreen1 = 15;
- 		}
- 
- 		int iMinBlue1 = iColor1Blue - (int)a_uiRadius;
-@@ -869,7 +869,7 @@ namespace Etc
- 		int iMaxBlue1 = iColor1Blue + (int)a_uiRadius;
- 		if (iMaxBlue1 > 15)
- 		{
--			iMinBlue1 = 15;
-+			iMaxBlue1 = 15;
- 		}
- 
- 		int iColor2Red = m_frgbaOriginalColor2_TAndH.IntRed(15.0f);
-@@ -884,7 +884,7 @@ namespace Etc
- 		int iMaxRed2 = iColor2Red + (int)a_uiRadius;
- 		if (iMaxRed2 > 15)
- 		{
--			iMinRed2 = 15;
-+			iMaxRed2 = 15;
- 		}
- 
- 		int iMinGreen2 = iColor2Green - (int)a_uiRadius;
-@@ -895,7 +895,7 @@ namespace Etc
- 		int iMaxGreen2 = iColor2Green + (int)a_uiRadius;
- 		if (iMaxGreen2 > 15)
- 		{
--			iMinGreen2 = 15;
-+			iMaxGreen2 = 15;
- 		}
- 
- 		int iMinBlue2 = iColor2Blue - (int)a_uiRadius;
-@@ -906,7 +906,7 @@ namespace Etc
- 		int iMaxBlue2 = iColor2Blue + (int)a_uiRadius;
- 		if (iMaxBlue2 > 15)
- 		{
--			iMinBlue2 = 15;
-+			iMaxBlue2 = 15;
- 		}
- 
- 		for (unsigned int uiDistance = 0; uiDistance < TH_DISTANCES; uiDistance++)
-@@ -1108,7 +1108,7 @@ namespace Etc
- 		int iMaxRed1 = iColor1Red + (int)a_uiRadius;
- 		if (iMaxRed1 > 15)
- 		{
--			iMinRed1 = 15;
-+			iMaxRed1 = 15;
- 		}
- 
- 		int iMinGreen1 = iColor1Green - (int)a_uiRadius;
-@@ -1119,7 +1119,7 @@ namespace Etc
- 		int iMaxGreen1 = iColor1Green + (int)a_uiRadius;
- 		if (iMaxGreen1 > 15)
- 		{
--			iMinGreen1 = 15;
-+			iMaxGreen1 = 15;
- 		}
- 
- 		int iMinBlue1 = iColor1Blue - (int)a_uiRadius;
-@@ -1130,7 +1130,7 @@ namespace Etc
- 		int iMaxBlue1 = iColor1Blue + (int)a_uiRadius;
- 		if (iMaxBlue1 > 15)
- 		{
--			iMinBlue1 = 15;
-+			iMaxBlue1 = 15;
- 		}
- 
- 		int iColor2Red = m_frgbaOriginalColor2_TAndH.IntRed(15.0f);
-@@ -1145,7 +1145,7 @@ namespace Etc
- 		int iMaxRed2 = iColor2Red + (int)a_uiRadius;
- 		if (iMaxRed2 > 15)
- 		{
--			iMinRed2 = 15;
-+			iMaxRed2 = 15;
- 		}
- 
- 		int iMinGreen2 = iColor2Green - (int)a_uiRadius;
-@@ -1156,7 +1156,7 @@ namespace Etc
- 		int iMaxGreen2 = iColor2Green + (int)a_uiRadius;
- 		if (iMaxGreen2 > 15)
- 		{
--			iMinGreen2 = 15;
-+			iMaxGreen2 = 15;
- 		}
- 
- 		int iMinBlue2 = iColor2Blue - (int)a_uiRadius;
-@@ -1167,7 +1167,7 @@ namespace Etc
- 		int iMaxBlue2 = iColor2Blue + (int)a_uiRadius;
- 		if (iMaxBlue2 > 15)
- 		{
--			iMinBlue2 = 15;
-+			iMaxBlue2 = 15;
- 		}
- 
- 		for (unsigned int uiDistance = 0; uiDistance < TH_DISTANCES; uiDistance++)