Merge pull request #10889 from shuffle2/spng

replace libpng with libspng

.gitmodules

@@ -32,3 +32,8 @@
 	path = Externals/zlib-ng/zlib-ng
 	url = https://github.com/zlib-ng/zlib-ng.git
 	shallow = true
+[submodule "Externals/libspng/libspng"]
+	path = Externals/libspng/libspng
+	url = https://github.com/randy408/libspng.git
+	branch = v0.7.2
+	shallow = true

CMakeLists.txt

@@ -53,7 +53,6 @@ if(NOT ANDROID)
 endif()
 
 option(USE_SHARED_ENET "Use shared libenet if found rather than Dolphin's soon-to-compatibly-diverge version" OFF)
-option(USE_SHARED_LIBPNG "Use shared libpng if found" ON)
 option(USE_UPNP "Enables UPnP port mapping support" ON)
 option(ENABLE_NOGUI "Enable NoGUI frontend" ON)
 option(ENABLE_QT "Enable Qt (Default)" ON)
@@ -411,9 +410,6 @@ if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
   find_library(IOB_LIBRARY IOBluetooth)
   find_library(IOK_LIBRARY IOKit)
   find_library(OPENGL_LIBRARY OpenGL)
-
-  # We don't want to use shared libpng.
-  set(USE_SHARED_LIBPNG OFF)
 endif()
 
 if(ENABLE_LTO)
@@ -810,17 +806,7 @@ else()
   set(LZO lzo2)
 endif()
 
-if(USE_SHARED_LIBPNG)
-  check_lib(PNG libpng png png.h QUIET)
-endif()
-if (PNG_FOUND)
-  message(STATUS "Using shared libpng")
-else()
-  check_vendoring_approved(libpng)
-  message(STATUS "Using static libpng from Externals")
-  add_subdirectory(Externals/libpng)
-  set(PNG png)
-endif()
+add_subdirectory(Externals/libspng)
 
 # Using static FreeSurround from Externals
 # There is no system FreeSurround library.

Externals/ExternalsReferenceAll.props

@@ -52,8 +52,8 @@
     <ProjectReference Include="$(ExternalsDir)liblzma\liblzma.vcxproj">
       <Project>{055a775f-b4f5-4970-9240-f6cf7661f37b}</Project>
     </ProjectReference>
-    <ProjectReference Include="$(ExternalsDir)libpng\png\png.vcxproj">
-      <Project>{4c9f135b-a85e-430c-bad4-4c67ef5fc12c}</Project>
+    <ProjectReference Include="$(ExternalsDir)libspng\spng.vcxproj">
+      <Project>{447B7B1E-1D74-4AEF-B2B9-6EB41C5D5313}</Project>
     </ProjectReference>
     <ProjectReference Include="$(ExternalsDir)libusb\libusb-1.0.vcxproj">
       <Project>{349ee8f9-7d25-4909-aaf5-ff3fade72187}</Project>