diff --git a/.appveyor.yml b/.appveyor.yml
index 07e7bc4..932a280 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -13,58 +13,57 @@
   matrix:
     - TOOLCHAIN: vstudio
       AUTOMATION: cmake
-      CI_CMAKE_GENERATOR: Visual Studio 16 2019
-      CI_CMAKE_GENERATOR_PLATFORM: Win32
+      ARCH: x86
     - TOOLCHAIN: vstudio
       AUTOMATION: cmake
-      CI_CMAKE_GENERATOR: Visual Studio 16 2019
-      CI_CMAKE_GENERATOR_PLATFORM: X64
+      ARCH: x64
     - TOOLCHAIN: vstudio
       AUTOMATION: cmake
-      CI_CMAKE_GENERATOR: Visual Studio 16 2019
-      CI_CMAKE_GENERATOR_PLATFORM: ARM64
+      ARCH: arm64
       CI_NO_TEST: 1
     - TOOLCHAIN: msys2
       AUTOMATION: cmake
-      CI_CMAKE_GENERATOR: Unix Makefiles
-      CI_CC: i686-w64-mingw32-gcc
+      ARCH: i686
     - TOOLCHAIN: msys2
       AUTOMATION: cmake
-      CI_CMAKE_GENERATOR: Unix Makefiles
-      CI_CC: x86_64-w64-mingw32-gcc
+      ARCH: x86_64
     - TOOLCHAIN: msys2
       AUTOMATION: autotools
-      CI_CC: i686-w64-mingw32-gcc
+      ARCH: i686
     - TOOLCHAIN: msys2
       AUTOMATION: autotools
-      CI_CC: x86_64-w64-mingw32-gcc
+      ARCH: x86_64
     - TOOLCHAIN: msys2
       AUTOMATION: legacy
-      CI_CC: i686-w64-mingw32-gcc
+      ARCH: i686
     - TOOLCHAIN: msys2
       AUTOMATION: legacy
-      CI_CC: x86_64-w64-mingw32-gcc
+      ARCH: x86_64
 
 install:
-  - 'if "%TOOLCHAIN%"=="vstudio" if "%CI_CMAKE_GENERATOR_PLATFORM%"=="Win32" C:\tools\vcpkg\vcpkg.exe install zlib:x86-windows'
-  - 'if "%TOOLCHAIN%"=="vstudio" if "%CI_CMAKE_GENERATOR_PLATFORM%"=="X64" C:\tools\vcpkg\vcpkg.exe install zlib:x64-windows'
-  - 'if "%TOOLCHAIN%"=="vstudio" if "%CI_CMAKE_GENERATOR_PLATFORM%"=="ARM64" C:\tools\vcpkg\vcpkg.exe install zlib:arm64-windows'
+  - 'if "%TOOLCHAIN%"=="vstudio" C:\tools\vcpkg\vcpkg.exe install zlib:%ARCH%-windows'
   - 'if "%TOOLCHAIN%"=="vstudio" C:\tools\vcpkg\vcpkg.exe integrate install'
 
 before_build:
   - 'if "%TOOLCHAIN%"=="vstudio" set CI_CMAKE_VARS=-DCMAKE_TOOLCHAIN_FILE=C:\tools\vcpkg\scripts\buildsystems\vcpkg.cmake'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%CI_CC%"=="i686-w64-mingw32-gcc" set PATH=C:\msys64\mingw32\bin;%PATH%'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%CI_CC%"=="x86_64-w64-mingw32-gcc" set PATH=C:\msys64\mingw64\bin;%PATH%'
+  - 'if "%TOOLCHAIN%"=="vstudio" set CI_CMAKE_GENERATOR=Visual Studio 16 2019'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="x86" set CI_CMAKE_GENERATOR_PLATFORM=Win32'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="x64" set CI_CMAKE_GENERATOR_PLATFORM=X64'
+  - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="arm64" set CI_CMAKE_GENERATOR_PLATFORM=ARM64'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" set CI_CMAKE_GENERATOR=Unix Makefiles'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="i686" set PATH=C:\msys64\mingw32\bin;%PATH%'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="x86_64" set PATH=C:\msys64\mingw64\bin;%PATH%'
+  - 'if "%TOOLCHAIN%"=="msys2" set CI_CC=%ARCH%-w64-mingw32-gcc'
   - 'set CI_CMAKE_BUILD_FLAGS=--parallel 2'
   - 'set CI_CTEST_FLAGS=--parallel 2'
   - 'set CI_MAKE_FLAGS=-j2'
   - 'set CI_LEGACY_MAKEFILES=scripts/makefile.gcc scripts/makefile.msys scripts/makefile.std'
 
 build_script:
-  - 'if "%TOOLCHAIN%"=="vstudio" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\scripts\ci_cmake.sh"'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\scripts\ci_cmake.sh"'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="autotools" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\scripts\ci_autotools.sh"'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="legacy" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\scripts\ci_legacy.sh"'
+  - 'if "%TOOLCHAIN%"=="vstudio" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_cmake.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_cmake.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="autotools" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_autotools.sh"'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="legacy" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_legacy.sh"'
 
 cache:
   - C:\tools\vcpkg\installed
diff --git a/.travis.yml b/.travis.yml
index e2b07ea..3c1eb0c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -38,6 +38,4 @@
   - 'export CI_LEGACY_MAKEFILES="scripts/makefile.$TRAVIS_COMPILER scripts/makefile.std"'
 
 script:
-  - './scripts/ci_$AUTOMATION.sh'
-
-sudo: false
+  - './ci/ci_$AUTOMATION.sh'
diff --git a/AUTHORS b/AUTHORS
index c1f119b..45fb425 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -38,8 +38,8 @@
    - Dan Field
 
 The build projects, the build scripts, the test scripts, and other
-files in the "projects", "scripts" and "tests" directories, have other
-copyright owners, but are released under the libpng license.
+files in the "ci", "projects", "scripts" and "tests" directories, have
+other copyright owners, but are released under the libpng license.
 
 Some files in the "contrib" directory, and some tools-generated files
 that are distributed with libpng, have other copyright owners, and are
diff --git a/scripts/ci_autotools.sh b/ci/ci_autotools.sh
similarity index 79%
rename from scripts/ci_autotools.sh
rename to ci/ci_autotools.sh
index 8cc70fe..ce9157b 100755
--- a/scripts/ci_autotools.sh
+++ b/ci/ci_autotools.sh
@@ -7,13 +7,13 @@
 # Copyright (c) 2019-2020 Cosmin Truta.
 #
 # This software is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer and license
-# in png.h.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h.
 
-CI_SCRIPTNAME="$(basename "$0")"
-CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
-CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
-CI_BUILDDIR="$CI_SRCDIR/out/autotools.build"
+readonly CI_SCRIPTNAME="$(basename "$0")"
+readonly CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
+readonly CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
+readonly CI_BUILDDIR="$CI_SRCDIR/out/autotools.build"
 
 function ci_info {
     printf >&2 "%s: %s\\n" "$CI_SCRIPTNAME" "$*"
@@ -52,11 +52,11 @@
 }
 
 function ci_build_autotools {
-    # Initialize the configure environment.
-    [[ $CI_CC ]] && export CC="$CI_CC"
-    [[ $CI_CC_FLAGS ]] && export CFLAGS="$CI_CC_FLAGS"
-    [[ $CI_SANITIZERS ]] && export CFLAGS="-fsanitize=$CI_SANITIZERS -O2 $CFLAGS"
-    # Build.
+    # Export the configure build environment.
+    [[ $CI_CC ]] && ci_spawn export CC="$CI_CC"
+    [[ $CI_CC_FLAGS ]] && ci_spawn export CFLAGS="$CI_CC_FLAGS"
+    [[ $CI_SANITIZERS ]] && ci_spawn export CFLAGS="-fsanitize=$CI_SANITIZERS -O2 $CFLAGS"
+    # Build!
     ci_spawn rm -fr "$CI_BUILDDIR"
     ci_spawn mkdir -p "$CI_BUILDDIR"
     ci_spawn cd "$CI_BUILDDIR"
diff --git a/scripts/ci_cmake.sh b/ci/ci_cmake.sh
similarity index 84%
rename from scripts/ci_cmake.sh
rename to ci/ci_cmake.sh
index c868ef8..1a4e596 100755
--- a/scripts/ci_cmake.sh
+++ b/ci/ci_cmake.sh
@@ -7,13 +7,13 @@
 # Copyright (c) 2019-2020 Cosmin Truta.
 #
 # This software is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer and license
-# in png.h.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h.
 
-CI_SCRIPTNAME="$(basename "$0")"
-CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
-CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
-CI_BUILDDIR="$CI_SRCDIR/out/cmake.build"
+readonly CI_SCRIPTNAME="$(basename "$0")"
+readonly CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
+readonly CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
+readonly CI_BUILDDIR="$CI_SRCDIR/out/cmake.build"
 
 function ci_info {
     printf >&2 "%s: %s\\n" "$CI_SCRIPTNAME" "$*"
@@ -53,14 +53,12 @@
     ci_info "environment option: \$CI_SANITIZERS='$CI_SANITIZERS'"
     ci_info "environment option: \$CI_NO_TEST='$CI_NO_TEST'"
     ci_info "environment option: \$CI_NO_CLEAN='$CI_NO_CLEAN'"
+    # Print the CMake/CTest program versions.
+    ci_spawn "$(command -v "$CI_CMAKE")" --version
+    ci_spawn "$(command -v "$CI_CTEST")" --version
 }
 
 function ci_build_cmake {
-    # Initialize the CMake environment.
-    [[ $CI_CMAKE_GENERATOR ]] &&
-        export CMAKE_GENERATOR="$CI_CMAKE_GENERATOR"
-    [[ $CI_CMAKE_GENERATOR_PLATFORM ]] &&
-        export CMAKE_GENERATOR_PLATFORM="$CI_CMAKE_GENERATOR_PLATFORM"
     # Initialize ALL_CC_FLAGS as a string.
     local ALL_CC_FLAGS="$CI_CC_FLAGS"
     [[ $CI_SANITIZERS ]] && ALL_CC_FLAGS="-fsanitize=$CI_SANITIZERS $ALL_CC_FLAGS"
@@ -71,10 +69,14 @@
     [[ $ALL_CC_FLAGS ]] && ALL_CMAKE_VARS+=("-DCMAKE_C_FLAGS=$ALL_CC_FLAGS")
     ALL_CMAKE_VARS+=("-DCMAKE_BUILD_TYPE=$CI_CMAKE_BUILD_TYPE")
     ALL_CMAKE_VARS+=("-DCMAKE_VERBOSE_MAKEFILE=ON")
+    [[ $CI_NO_TEST ]] && ALL_CMAKE_VARS+=("-DPNG_TESTS=OFF")
     ALL_CMAKE_VARS+=($CI_CMAKE_VARS)
-    # Build.
-    ci_spawn "$(command -v "$CI_CMAKE")" --version
-    ci_spawn "$(command -v "$CI_CTEST")" --version
+    # Export the CMake build environment.
+    [[ $CI_CMAKE_GENERATOR ]] &&
+        ci_spawn export CMAKE_GENERATOR="$CI_CMAKE_GENERATOR"
+    [[ $CI_CMAKE_GENERATOR_PLATFORM ]] &&
+        ci_spawn export CMAKE_GENERATOR_PLATFORM="$CI_CMAKE_GENERATOR_PLATFORM"
+    # Build!
     ci_spawn "$CI_CMAKE" -E remove_directory "$CI_BUILDDIR"
     ci_spawn "$CI_CMAKE" -E make_directory "$CI_BUILDDIR"
     ci_spawn cd "$CI_BUILDDIR"
diff --git a/scripts/ci_legacy.sh b/ci/ci_legacy.sh
similarity index 90%
rename from scripts/ci_legacy.sh
rename to ci/ci_legacy.sh
index 77f73c9..a933894 100755
--- a/scripts/ci_legacy.sh
+++ b/ci/ci_legacy.sh
@@ -7,13 +7,13 @@
 # Copyright (c) 2019-2020 Cosmin Truta.
 #
 # This software is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer and license
-# in png.h.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h.
 
-CI_SCRIPTNAME="$(basename "$0")"
-CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
-CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
-CI_BUILDDIR="$CI_SRCDIR"
+readonly CI_SCRIPTNAME="$(basename "$0")"
+readonly CI_SCRIPTDIR="$(cd "$(dirname "$0")" && pwd)"
+readonly CI_SRCDIR="$(dirname "$CI_SCRIPTDIR")"
+readonly CI_BUILDDIR="$CI_SRCDIR"
 
 function ci_info {
     printf >&2 "%s: %s\\n" "$CI_SCRIPTNAME" "$*"
@@ -79,12 +79,12 @@
     [[ $ALL_LD_FLAGS ]] && ALL_MAKE_ARGS+=("LDFLAGS=$ALL_LD_FLAGS")
     ALL_MAKE_ARGS+=("LIBS=$CI_LIBS")
     ALL_MAKE_ARGS+=($CI_MAKE_VARS)
-    # Build.
+    # Build!
     ci_spawn cd "$CI_SRCDIR"
-    [[ $CI_LEGACY_MAKEFILES ]] || ci_err "bad or missing: \$CI_LEGACY_MAKEFILES"
     local MY_MAKEFILE
     for MY_MAKEFILE in $CI_LEGACY_MAKEFILES
     do
+        ci_info "using makefile: $MY_MAKEFILE"
         ci_spawn "$CI_MAKE" "${ALL_MAKE_ARGS[@]}" -f $MY_MAKEFILE
         [[ $CI_NO_TEST ]] || ci_spawn "$CI_MAKE" "${ALL_MAKE_ARGS[@]}" -f $MY_MAKEFILE test
         [[ $CI_NO_CLEAN ]] || ci_spawn "$CI_MAKE" "${ALL_MAKE_ARGS[@]}" -f $MY_MAKEFILE clean