COMP: Add ARM sources to libpng build

This compilation of the function identified in the name mangling header
addresses linker errors with the Apple Silicon ARM64 system following
their requirement in the logic at:

  https://github.com/InsightSoftwareConsortium/ITK/blob/1e0755ce4ceb79823157f68ed1c6db317df2679d/Modules/ThirdParty/PNG/src/itkpng/pngpriv.h#L160-L165

Modules/ThirdParty/PNG/src/itkpng/CMakeLists.txt

@@ -11,6 +11,13 @@ pngerror.c  pngpread.c  pngrutil.c  pngwutil.c
 pngread.c   pngset.c   pngwio.c
 )
 
+if("${CMAKE_SYSTEM_PROCESSOR}" MATCHES "arm")
+  list(APPEND PNG_SRCS
+    arm/arm_init.c
+    arm/filter_neon_intrinsics.c
+    arm/palette_neon_intrinsics.c)
+endif()
+
 if(WIN32)
   if(BUILD_SHARED_LIBS)
     add_definitions(-DPNG_BUILD_DLL)

Modules/ThirdParty/PNG/src/itkpng/itk_png_mangle.h

@@ -71,6 +71,8 @@ nm lib/libitkpng-4.12.a 2> /dev/null | grep " T \| D \| R " |
 #define png_destroy_write_struct itk_png_destroy_write_struct
 #define png_do_bgr itk_png_do_bgr
 #define png_do_check_palette_indexes itk_png_do_check_palette_indexes
+#define png_do_expand_palette_rgb8_neon itk_png_do_expand_palette_rgb8_neon
+#define png_do_expand_palette_rgba8_neon itk_png_do_expand_palette_rgba8_neon
 #define png_do_invert itk_png_do_invert
 #define png_do_packswap itk_png_do_packswap
 #define png_do_read_interlace itk_png_do_read_interlace
@@ -208,6 +210,7 @@ nm lib/libitkpng-4.12.a 2> /dev/null | grep " T \| D \| R " |
 #define png_image_write_to_memory itk_png_image_write_to_memory
 #define png_image_write_to_stdio itk_png_image_write_to_stdio
 #define png_info_init_3 itk_png_info_init_3
+#define png_init_filter_functions_neon itk_png_init_filter_functions_neon
 #define png_init_io itk_png_init_io
 #define png_init_read_transformations itk_png_init_read_transformations
 #define png_longjmp itk_png_longjmp
@@ -259,6 +262,7 @@ nm lib/libitkpng-4.12.a 2> /dev/null | grep " T \| D \| R " |
 #define png_reciprocal2 itk_png_reciprocal2
 #define png_reset_crc itk_png_reset_crc
 #define png_reset_zstream itk_png_reset_zstream
+#define png_riffle_palette_neon itk_png_riffle_palette_neon
 #define png_sRGB_base itk_png_sRGB_base
 #define png_sRGB_delta itk_png_sRGB_delta
 #define png_sRGB_table itk_png_sRGB_table