Get libpng build to work with ZLIBConfig.cmake

png/CMakeLists.txt

@@ -30,7 +30,8 @@ if (ENABLE_PNG)
   ExternalProject_Add(PNG_BLD
     URL "${CMAKE_CURRENT_SOURCE_DIR}/libpng"
     BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
-    PATCH_COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/png.patch
+    PATCH_COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/png_cmake.patch
+    COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/png_zlib.patch
     CMAKE_ARGS
     -DCMAKE_FIND_PACKAGE_PREFER_CONFIG=ON
     ${BUILD_TYPE_SPECIFIER}

png/png_cmake.patch

@@ -0,0 +1,70 @@
+diff -Naur libpng/CMakeLists.txt PNG_BLD/CMakeLists.txt
+--- libpng/CMakeLists.txt	2024-10-11 10:39:06.421433191 -0400
++++ PNG_BLD/CMakeLists.txt	2024-10-11 10:40:45.921699021 -0400
+@@ -47,8 +47,10 @@
+ # Previously, we used to set CMAKE_DEBUG_POSTFIX globally. That variable should
+ # not be cached, however, because doing so would affect all projects processed
+ # after libpng, in unexpected and undesirable ways.
+-set(PNG_DEBUG_POSTFIX "d"
+-    CACHE STRING "Postfix to append to library file names under the Debug configuration")
++if(NOT PNG_NO_DEBUG_POSTFIX)
++  set(PNG_DEBUG_POSTFIX "d"
++      CACHE STRING "Postfix to append to library file names under the Debug configuration")
++endif(NOT PNG_NO_DEBUG_POSTFIX)
+
+ # Allow the users to import their own extra configuration settings.
+ set(DFA_XTRA ""
+@@ -488,10 +490,9 @@
+
+   if(PNG_PREFIX)
+     set(PNGLIBCONF_H_EXTRA_DEPENDS
+-        "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
+-        "${CMAKE_CURRENT_SOURCE_DIR}/scripts/macro.lst")
++        png_scripts_prefix_out)
+     set(PNGPREFIX_H_EXTRA_DEPENDS
+-        "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
++        png_scripts_intprefix_out)
+   endif()
+
+   generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
+@@ -675,15 +676,15 @@
+   # We are on a Unix or Unix-like toolchain like the GNU toolchain on Windows.
+   # Library file names are expected to have an implicit prefix such as "lib".
+   # Let CMake prepend and append its usual prefixes and suffixes by default.
+-  set(PNG_SHARED_OUTPUT_NAME "png${PNGLIB_ABI_VERSION}")
+-  set(PNG_STATIC_OUTPUT_NAME "png${PNGLIB_ABI_VERSION}")
++  set(PNG_SHARED_OUTPUT_NAME "png_brl${PNGLIB_ABI_VERSION}")
++  set(PNG_STATIC_OUTPUT_NAME "png_brl${PNGLIB_ABI_VERSION}")
+ else()
+   # We are, most likely, on a Windows toolchain like MSVC, Clang on Windows,
+   # Borland/Embarcadero, etc. We need to specify the "libpng" name explicitly.
+   # We also need to use a custom suffix, in order to distinguish between the
+   # shared import library name and the static library name.
+-  set(PNG_SHARED_OUTPUT_NAME "libpng${PNGLIB_ABI_VERSION}")
+-  set(PNG_STATIC_OUTPUT_NAME "libpng${PNGLIB_ABI_VERSION}_static")
++  set(PNG_SHARED_OUTPUT_NAME "libpng_brl${PNGLIB_ABI_VERSION}")
++  set(PNG_STATIC_OUTPUT_NAME "libpng_brl${PNGLIB_ABI_VERSION}_static")
+ endif()
+
+ if(PNG_SHARED)
+@@ -1072,16 +1073,16 @@
+   if(PNG_SHARED)
+     # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
+     if(NOT WIN32 OR CYGWIN OR MINGW)
+-      create_symlink(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png_shared)
+-      install(FILES $<TARGET_LINKER_FILE_DIR:png_shared>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
++      create_symlink(libpng_brl${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png_shared)
++      install(FILES $<TARGET_LINKER_FILE_DIR:png_shared>/libpng_brl${CMAKE_SHARED_LIBRARY_SUFFIX}
+               DESTINATION ${CMAKE_INSTALL_LIBDIR})
+     endif()
+   endif()
+
+   if(PNG_STATIC)
+     if(NOT WIN32 OR CYGWIN OR MINGW)
+-      create_symlink(libpng${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
+-      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
++      create_symlink(libpng_brl${CMAKE_STATIC_LIBRARY_SUFFIX} TARGET png_static)
++      install(FILES $<TARGET_LINKER_FILE_DIR:png_static>/libpng_brl${CMAKE_STATIC_LIBRARY_SUFFIX}
+               DESTINATION ${CMAKE_INSTALL_LIBDIR})
+     endif()
+   endif()

png/png_zlib.patch

@@ -0,0 +1,12 @@
+diff -Naur libpng/scripts/pnglibconf.dfa PNG_BLD/scripts/pnglibconf.dfa
+--- libpng/scripts/pnglibconf.dfa	2024-10-11 10:48:58.913083752 -0400
++++ PNG_BLD/scripts/pnglibconf.dfa	2024-10-11 10:48:27.026205664 -0400
+@@ -343,7 +343,7 @@
+ # The TEXT values are the defaults when writing compressed text (all forms)
+
+ # Include the zlib header so that the defaults below are known
+-@#  include <zlib.h>
++@#  include "zlib.h"
+
+ # The '@' here means to substitute the value when pnglibconf.h is built
+ setting Z_DEFAULT_COMPRESSION default @Z_DEFAULT_COMPRESSION