GD-2.90

Changes for version 2.90

JXL: newFromJxl/newFromJxlData readers, jxl() writer (lossless/distance/effort), magic-byte autodetection in new().
UHDR: new GD::UHDR class (newFromFile/newFromData, width/height/ hasGainMap, resize/crop/rotate/mirror, file/write, getSdr).
Work around libgd 2.4.0 gd.h no longer declaring gdImageBoundsSafe().
IMAGEQUANT: trueColorToPaletteSetMethod/SetQuality and the GD_QUANT_* constants for the libimagequant-backed quantizer. Guard for installations without libimagequant. Fix imagequant feature autodetection in Makefile.PL (libimagequant surfaces in gdlib.pc's Libs.private, not Requires.private).
Embed rpath (Linux) and fix stale blib/lib/GD/Image.pm so 'make test' reliably exercises the just-configured libgd (GH #21 test infra); fix GD_LIQ detection from the deprecated gdlib-config script.
Add Affine transformations (GH #21): GD::Image affine matrix builders (affineIdentity/Scale/Rotate/ShearHorizontal/ ShearVertical/Translate/Concat/Invert/Flip/Expansion/ Rectilinear/Equal/ApplyToPoint) and transformAffineGetImage/ transformAffineCopy/transformAffineBoundingBox, wrapping gdAffine*/gdTransformAffine* (libgd >= 2.1.0). Fix GD_AFFINE_* constant visibility (same enum/#ifdef issue as GD_QUANT_*).
Add more previously-unbound libgd methods (libgd >= 2.1.0 unless noted): paletteToTrueColor, crop, cropAuto, cropThreshold, colorReplace, colorReplaceArray, colorReplaceThreshold, convolution, resolution; cloneImage, getTrueColorPixel, perceptualDiff (libgd >= 2.4.0). clone() now uses the native gdImageClone() when available, fixing truecolor-ness loss on the old new()+copy() fallback. Fix GD_CROP_* constant visibility (same enum/#ifdef issue as GD_QUANT_*).
Animated WebP support (libgd >= 2.4.0): new GD::WebpAnimWriter (new/addImage/finish, wrapping gdWebpWriteOpenPtr/AddImage/ PtrFinish) and GD::WebpAnimReader (newFromData/info/nextImage, wrapping gdWebpReadOpenCtx/GetInfo/NextImage) classes.
Animated/multi-image JXL support (libgd >= 2.4.0): new GD::JxlAnimWriter (new/addImage/finish, wrapping gdJxlWriteOpenPtr/AddImage/PtrFinish) and GD::JxlAnimReader (newFromData/info/nextImage, wrapping gdJxlReadOpenCtx/ GetInfo/NextImage) classes, mirroring GD::WebpAnimReader/Writer.
Multi-page TIFF support (libgd >= 2.4.0): new GD::TiffMultiWriter (new/addImage/finish, wrapping gdTiffWriteOpenPtr/AddImage/PtrFinish) and GD::TiffMultiReader (newFromData/info/nextImage, wrapping gdTiffReadOpenCtx/ GetInfo/NextImage) classes, mirroring GD::WebpAnimReader/Writer (pages have no per-page delay; nextImage() returns a page-info hashref instead). Also adds the GD_TIFF_* writer option constants (colorspace, compression, resolution unit, alpha type).
Per-format header introspection (libgd >= 2.4.0): new GD::Image->pngInfoData/jpegInfoData/gifInfoData/bmpInfoData/ avifInfoData/heifInfoData class methods, wrapping gd{Png,Jpeg,Gif,Bmp,Avif,Heif}GetInfoCtx. Each reads just the container facts (dimensions, bit depth, and similar) from an in-memory buffer without fully decoding the image.
Fixed a longstanding bug in the in-memory gdIOCtx used by every newFrom*Data()/*InfoData() method: its getC() callback never advanced the read position, so any decoder reading a buffer byte-by-byte (as the new bmpInfoData()'s BMP header parser does) would spin re-reading the first byte forever. PNG, JPEG, GIF, WebP, TIFF, JXL, AVIF and HEIF decoding were unaffected because they read through the bulk getBuf() callback instead, which was already correct.
Worked around inconsistent success/failure return conventions across libgd's new Get*InfoCtx functions: gdPngGetInfoCtx, gdJpegGetInfoCtx, gdAvifGetInfoCtx and gdHeifGetInfoCtx all return 0 on success despite two of their own header comments claiming the opposite, while gdGifGetInfoCtx and gdBmpGetInfoCtx return 1 on success as documented.