[build] Update libpng, fix build warnings

Update libpng 1.6.40 : 1.6.50
Avoid CMake deprecation warnings
Update how zlib is imported based on libpng CMake changes
Bump version
Update copyright year

Author: fhanau

src/CMakeLists.txt

@@ -1,14 +1,16 @@
-cmake_minimum_required(VERSION 3.8 FATAL_ERROR)
-project(ect VERSION 0.9.5 LANGUAGES CXX C)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
+project(ect VERSION 0.9.6 LANGUAGES CXX C)
 cmake_policy(SET CMP0048 NEW)
+# Allow use of ZLIB_ROOT
+cmake_policy(SET CMP0074 NEW)
 
 include(GNUInstallDirs)
 
 #Note that C++11 is still supported, but using it will cause the directory support to be disabled.
 set (CMAKE_CXX_STANDARD 17)
 
 if(NOT CMAKE_BUILD_TYPE)
-	set(CMAKE_BUILD_TYPE Release)
+  set(CMAKE_BUILD_TYPE Release)
 endif()
 
 # Check that submodules are present only if source was downloaded with git
@@ -17,37 +19,38 @@ if(EXISTS "${CMAKE_SOURCE_DIR}/../.git" AND NOT EXISTS "${CMAKE_SOURCE_DIR}/../s
 endif()
 
 add_executable(ect
-	main.cpp
-	gztools.cpp
-	jpegtran.cpp
-	LzFind.c
-	support.cpp
-	zopflipng.cpp
-	# Add headers so they get added to things like Xcode projects
-	gztools.h
-	LzFind.h
-	main.h
-	pngusr.h
-	support.h
-	mozjpeg/transupp.c)
+  main.cpp
+  gztools.cpp
+  jpegtran.cpp
+  LzFind.c
+  support.cpp
+  zopflipng.cpp
+  # Add headers so they get added to things like Xcode projects
+  gztools.h
+  LzFind.h
+  main.h
+  pngusr.h
+  support.h
+  mozjpeg/transupp.c)
 
 add_executable(ect::ect ALIAS ect)
 
 if(MINGW)
-	add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-mno-ms-bitfields>)
-	add_compile_options($<$<COMPILE_LANGUAGE:C>:-mno-ms-bitfields>)
+  add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-mno-ms-bitfields>)
+  add_compile_options($<$<COMPILE_LANGUAGE:C>:-mno-ms-bitfields>)
 endif()
 
 if(NOT MSVC)
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-sign-compare -Wno-unused -Wno-unused-parameter")
-	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wno-sign-compare -Wno-unused -Wno-unused-parameter")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-sign-compare -Wno-unused -Wno-unused-parameter")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wno-sign-compare -Wno-unused -Wno-unused-parameter")
 endif()
 
 # Use -Ofast in release builds
+# TODO: This is now deprecated in clang and likely makes little difference, switch back to -O3.
 foreach(var CMAKE_C_FLAGS_RELEASE CMAKE_C_FLAGS_RELWITHDEBINFO CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_RELWITHDEBINFO)
-	if(${var} MATCHES "-O(2|3)")
-		string(REGEX REPLACE "-O(2|3)" "-Ofast" ${var} "${${var}}")
-	endif()
+  if(${var} MATCHES "-O(2|3)")
+    string(REGEX REPLACE "-O(2|3)" "-Ofast" ${var} "${${var}}")
+  endif()
 endforeach()
 
 # Detect CPU type and whether we're building 64-bit or 32-bit code, courtesy of mozjpeg
@@ -61,10 +64,10 @@ foreach(ARCH ${CMAKE_OSX_ARCHITECTURES})
   math(EXPR COUNT "${COUNT}+1")
 endforeach()
 if(CMAKE_SYSTEM_PROCESSOR_LC MATCHES "x86_64" OR
-  CMAKE_SYSTEM_PROCESSOR_LC MATCHES "amd64" OR
-  CMAKE_SYSTEM_PROCESSOR_LC MATCHES "i[0-9]86" OR
-  CMAKE_SYSTEM_PROCESSOR_LC MATCHES "x86" OR
-  CMAKE_SYSTEM_PROCESSOR_LC MATCHES "ia32")
+    CMAKE_SYSTEM_PROCESSOR_LC MATCHES "amd64" OR
+    CMAKE_SYSTEM_PROCESSOR_LC MATCHES "i[0-9]86" OR
+    CMAKE_SYSTEM_PROCESSOR_LC MATCHES "x86" OR
+    CMAKE_SYSTEM_PROCESSOR_LC MATCHES "ia32")
   if(BITS EQUAL 64 OR CMAKE_C_COMPILER_ABI MATCHES "ELF X32")
     set(CPU_TYPE x86_64)
   else()
@@ -74,7 +77,7 @@ if(CMAKE_SYSTEM_PROCESSOR_LC MATCHES "x86_64" OR
     set(CMAKE_SYSTEM_PROCESSOR ${CPU_TYPE})
   endif()
 elseif(CMAKE_SYSTEM_PROCESSOR_LC STREQUAL "aarch64" OR
-  CMAKE_SYSTEM_PROCESSOR_LC MATCHES "^arm")
+    CMAKE_SYSTEM_PROCESSOR_LC MATCHES "^arm")
   if(BITS EQUAL 64)
     set(CPU_TYPE arm64)
   else()
@@ -84,8 +87,8 @@ else()
   set(CPU_TYPE ${CMAKE_SYSTEM_PROCESSOR_LC})
 endif()
 if(CMAKE_OSX_ARCHITECTURES MATCHES "x86_64" OR
-  CMAKE_OSX_ARCHITECTURES MATCHES "arm64" OR
-  CMAKE_OSX_ARCHITECTURES MATCHES "i386")
+    CMAKE_OSX_ARCHITECTURES MATCHES "arm64" OR
+    CMAKE_OSX_ARCHITECTURES MATCHES "i386")
   set(CPU_TYPE ${CMAKE_OSX_ARCHITECTURES})
 endif()
 if(MSVC_IDE AND CMAKE_GENERATOR_PLATFORM MATCHES "arm64")
@@ -121,6 +124,10 @@ endif()
 # Enable ZLIB_CONST for everything
 add_definitions(-DZLIB_CONST)
 
+# Ensure that zlib target points to our custom zlib zlib
+set(ZLIB_ROOT "zlib/")
+find_package(ZLIB)
+
 option(ECT_MULTITHREADING "Enable multithreaded processing support" ON)
 option(ECT_MP3_SUPPORT "Enable MP3 support (not currently working)" OFF)
 
@@ -136,33 +143,35 @@ set(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT FALSE)
 add_subdirectory(mozjpeg EXCLUDE_FROM_ALL)
 
 target_link_libraries(ect
-	leanify::leanify
-	lodepng::lodepng
-	miniz::miniz
-	optipng::optipng
-	zopfli::zopfli
-	zlib::zlib
-	jpeg-static)
+  leanify::leanify
+  lodepng::lodepng
+  miniz::miniz
+  optipng::optipng
+  zopfli::zopfli
+  zlib::zlib
+  jpeg-static
+)
 
 # mozjpeg generates some header files that we need to be able to include
 target_include_directories(ect
-	PRIVATE
-		${CMAKE_CURRENT_BINARY_DIR}/mozjpeg)
+  PRIVATE
+  ${CMAKE_CURRENT_BINARY_DIR}/mozjpeg
+)
 
 if(NOT ECT_MULTITHREADING)
-	target_compile_definitions(ect
-		PRIVATE
-			NOMULTI=1)
+  target_compile_definitions(ect
+    PRIVATE
+    NOMULTI=1)
 else()
-	find_package(Threads REQUIRED)
-	target_link_libraries(ect
-		Threads::Threads)
+  find_package(Threads REQUIRED)
+  target_link_libraries(ect
+    Threads::Threads)
 endif()
 
 if(ECT_MP3_SUPPORT)
-	target_compile_definitions(ect
-		PRIVATE
-			MP3_SUPPORTED=1)
+  target_compile_definitions(ect
+    PRIVATE
+    MP3_SUPPORTED=1)
 endif()
 
 install(TARGETS ect RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})

src/leanify/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 project(leanify LANGUAGES CXX)
 
 add_library(leanify

src/libpng

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 project(lodepng LANGUAGES CXX)
 
 add_library(lodepng

src/lodepng/CMakeLists.txt

@@ -1,7 +1,7 @@
 //  main.cpp
 //  Efficient Compression Tool
 //  Created by Felix Hanau on 12/19/14.
-//  Copyright (c) 2014-2024 Felix Hanau.
+//  Copyright (c) 2014-2025 Felix Hanau.
 
 #include "main.h"
 #include "support.h"
@@ -31,7 +31,7 @@ static std::atomic<long long> savings;
 static void Usage() {
     printf (
             "Efficient Compression Tool\n"
-            "(c) 2014-2024 Felix Hanau.\n"
+            "(c) 2014-2025 Felix Hanau.\n"
             "Version 0.9.5"
 #ifdef __DATE__
             " compiled on %s\n"

src/main.cpp

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 project(miniz LANGUAGES C)
 
 add_library(miniz

src/miniz/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 project(optipng LANGUAGES C CXX)
 
 add_library(optipng
@@ -15,8 +15,7 @@ add_library(optipng
 
 add_library(optipng::optipng ALIAS optipng)
 
-#make sure that we are using custom zlib and custom libpng options
-set(PNG_BUILD_ZLIB ON CACHE BOOL "use custom zlib within libpng" FORCE)
+# make sure that we are using custom libpng options
 set(PNG_ARM_NEON "on" CACHE STRING "Enable ARM NEON optimizations: on|off; on is default" FORCE)
 set(ZLIB_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/../zlib/ CACHE FILEPATH "custom zlib directory" FORCE)
 

src/mozjpeg

@@ -91,6 +91,17 @@
 #undef PNG_tIME_SUPPORTED
 #undef PNG_ARM_NEON_CHECK_SUPPORTED
 
+// Disable support for chunks added between 1.6.40..1.6.50
+#undef PNG_READ_cICP_SUPPORTED
+#undef PNG_READ_cLLI_SUPPORTED
+#undef PNG_READ_mDCV_SUPPORTED
+#undef PNG_WRITE_cICP_SUPPORTED
+#undef PNG_WRITE_cLLI_SUPPORTED
+#undef PNG_WRITE_mDCV_SUPPORTED
+#undef PNG_cICP_SUPPORTED
+#undef PNG_cLLI_SUPPORTED
+#undef PNG_mDCV_SUPPORTED
+
 #define PNG_IDAT_READ_SIZE 8192
 #define PNG_INFLATE_BUF_SIZE 32768
 #define PNG_ZBUF_SIZE 65536

src/optipng/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 project(zlib LANGUAGES C)
 
 add_library(zlib