Use patched version of zlib-ng to fix install name.

.github/workflows/wheels-dependencies.sh

@@ -26,6 +26,7 @@ else
     MB_ML_VER=${AUDITWHEEL_POLICY:9}
 fi
 PLAT=$CIBW_ARCHS
+PATCH_DIR=$(pwd)/patches
 
 # Define custom utilities
 source wheels/multibuild/common_utils.sh
@@ -36,7 +37,9 @@ fi
 
 ARCHIVE_SDIR=pillow-depends-main
 
-# Package versions for fresh source builds
+# Package versions for fresh source builds. Version numbers with "Patched"
+# annotations have a source code patch that is required for some platforms. If
+# you change those versions, ensure the patch is also updated.
 FREETYPE_VERSION=2.13.3
 HARFBUZZ_VERSION=10.2.0
 LIBPNG_VERSION=1.6.46
@@ -45,7 +48,7 @@ OPENJPEG_VERSION=2.5.3
 XZ_VERSION=5.6.4
 TIFF_VERSION=4.6.0
 LCMS2_VERSION=2.16
-ZLIB_NG_VERSION=2.2.3
+ZLIB_NG_VERSION=2.2.3  # patched
 LIBWEBP_VERSION=1.5.0
 BZIP2_VERSION=1.0.8
 LIBXCB_VERSION=1.17.0
@@ -69,7 +72,7 @@ function build_zlib_ng {
     if [ -e zlib-stamp ]; then return; fi
     fetch_unpack https://github.com/zlib-ng/zlib-ng/archive/$ZLIB_NG_VERSION.tar.gz zlib-ng-$ZLIB_NG_VERSION.tar.gz
     (cd zlib-ng-$ZLIB_NG_VERSION \
-        && ./configure --prefix=$BUILD_PREFIX --zlib-compat \
+        && ./configure --prefix=$BUILD_PREFIX --installnamedir=$BUILD_PREFIX/lib --zlib-compat \
         && make -j4 \
         && make install)
     touch zlib-stamp

.pre-commit-config.yaml

@@ -47,7 +47,7 @@ repos:
       - id: end-of-file-fixer
         exclude: ^Tests/images/
       - id: trailing-whitespace
-        exclude: ^.github/.*TEMPLATE|^Tests/(fonts|images)/
+        exclude: ^.github/.*TEMPLATE|^Tests/(fonts|images)/|^patches/*.patch
 
   - repo: https://github.com/python-jsonschema/check-jsonschema
     rev: 0.31.1

patches/README.md

@@ -0,0 +1,14 @@
+Although we try to use official sources for dependencies, sometimes the official
+sources don't support a platform (especially mobile platforms), or there's a bug
+fix/feature that is required to support Pillow's usage.
+
+This folder contains patches that must be applied to official sources, organized
+by the platforms that need those patches.
+
+Each patch is against the root of the unpacked official tarball, and is named by
+appending `.patch` to the end of the tarball that is to be patched. This
+includes the full version number; so if the version is bumped, the patch will
+at a minimum require a filename change.
+
+Wherever possible, these patches should be contributed upstream, in the hope that
+future Pillow versions won't need to maintain these patches.

patches/zlib-ng-2.2.3.tar.gz.patch

@@ -0,0 +1,65 @@
+# zlib-ng doesn't allow for manual specification of `--installnamedir`.
+#
+# Submitted upstream as https://github.com/zlib-ng/zlib-ng/pull/1867
+diff --git a/configure b/configure
+index 3487d092..91037f77 100755
+--- a/configure
++++ b/configure
+@@ -83,6 +83,7 @@ bindir=${bindir-'${exec_prefix}/bin'}
+ libdir=${libdir-'${exec_prefix}/lib'}
+ sharedlibdir=${sharedlibdir-'${libdir}'}
+ includedir=${includedir-'${prefix}/include'}
++installnamedir=${installnamedir-'@rpath'}
+ mandir=${mandir-'${prefix}/share/man'}
+ shared_ext='.so'
+ shared=1
+@@ -158,7 +159,7 @@ case "$1" in
+       echo 'usage:' | tee -a configure.log
+       echo '  configure [--prefix=PREFIX]  [--eprefix=EXPREFIX]' | tee -a configure.log
+       echo '    [--static] [--32] [--64] [--libdir=LIBDIR] [--sharedlibdir=LIBDIR]' | tee -a configure.log
+-      echo '    [--includedir=INCLUDEDIR] [--mandir=MANDIR] [--archs="-arch i386 -arch x86_64"]' | tee -a configure.log
++      echo '    [--includedir=INCLUDEDIR] [--installnamedir="@rpath"] [--mandir=MANDIR] [--archs="-arch i386 -arch x86_64"]' | tee -a configure.log
+       echo '    [--sprefix=SYMBOL_PREFIX]   Adds a prefix to all exported symbols' | tee -a configure.log
+       echo '    [--warn]                    Enables extra compiler warnings' | tee -a configure.log
+       echo '    [--debug]                   Enables extra debug prints during operation' | tee -a configure.log
+@@ -183,6 +184,7 @@ case "$1" in
+     -l*=* | --libdir=*) libdir=$(echo $1 | sed 's/.*=//'); shift ;;
+     --sharedlibdir=*) sharedlibdir=$(echo $1 | sed 's/.*=//'); shift ;;
+     -i*=* | --includedir=*) includedir=$(echo $1 | sed 's/.*=//');shift ;;
++    --installnamedir=*) installnamedir=$(echo $1 | sed 's/.*=//'); shift ;;
+     --mandir=*) mandir=$(echo $1 | sed 's/.*=//');shift ;;
+     -u*=* | --uname=*) uname=$(echo $1 | sed 's/.*=//');shift ;;
+     -p* | --prefix) prefix="$2"; shift; shift ;;
+@@ -470,7 +472,7 @@ if test "$gcc" -eq 1 && ($cc $CFLAGS -c $test.c) >> configure.log 2>&1; then
+              SHAREDLIBM=${LIBNAME}.$VER1$shared_ext
+              SHAREDTARGET=$SHAREDLIBV
+              LDSHARED=${LDSHARED-"$cc"}
+-             LDSHAREDFLAGS="-dynamiclib -install_name @rpath/${SHAREDLIBM} -compatibility_version ${VER1} -current_version ${VER3}"
++             LDSHAREDFLAGS="-dynamiclib -install_name ${installnamedir}/${SHAREDLIBM} -compatibility_version ${VER1} -current_version ${VER3}"
+              if "${CROSS_PREFIX}libtool" -V 2>&1 | grep Apple > /dev/null; then
+                  AR="${CROSS_PREFIX}libtool"
+              elif libtool -V 2>&1 | grep Apple > /dev/null; then
+@@ -1936,6 +1938,7 @@ echo TEST = $TEST >> configure.log
+ echo VER = $VER >> configure.log
+ echo exec_prefix = $exec_prefix >> configure.log
+ echo includedir = $includedir >> configure.log
++echo installnamedir = $installnamedir >> configure.log
+ echo bindir = $bindir >> configure.log
+ echo libdir = $libdir >> configure.log
+ echo mandir = $mandir >> configure.log
+@@ -2007,6 +2010,7 @@ sed < $SRCDIR/Makefile.in "
+ /^libdir *=/s#=.*#= $libdir#
+ /^sharedlibdir *=/s#=.*#= $sharedlibdir#
+ /^includedir *=/s#=.*#= $includedir#
++/^installnamedir *=/s#=.*#= $installnamedir#
+ /^mandir *=/s#=.*#= $mandir#
+ /^SRCDIR *=/s#=.*#=$SRCDIR#
+ /^INCLUDES *=/s#=.*#=$INCLUDES#
+@@ -2206,6 +2210,7 @@ sed < $SRCDIR/zlib.pc.in "
+ /^libdir *=/s#=.*#=$libdir#
+ /^sharedlibdir *=/s#=.*#=$sharedlibdir#
+ /^includedir *=/s#=.*#=$includedir#
++/^installnamedir *=/s#=.*#=$installnamedir#
+ /^mandir *=/s#=.*#=$mandir#
+ /^LDFLAGS *=/s#=.*#=$LDFLAGS#
+ " | sed -e "