Bring back compiling third_party/libpng in public.bzl

public.bzl

Index: public.bzl
diff --git a/public.bzl b/public.bzl
index f84abc0e6c9abca39049585ac77661f1fadd3d2c..5ba561231085bd349ae4ba4262c4882bc218abf7 100644
--- a/public.bzl
+++ b/public.bzl
@@ -79,6 +79,9 @@ BASE_SRCS_ALL = struct(
         "third_party/etc1/*.h",
         "third_party/ktx/*.cpp",
         "third_party/ktx/*.h",
+
+        "third_party/libpng/*.c",
+        "third_party/libpng/*.h",
     ],
     exclude = PRIVATE_HDRS_LIST + [
         # Exclude platform-dependent files.
@@ -383,6 +386,7 @@ INCLUDES = [
     "src/utils",
     "third_party/etc1",
     "third_party/ktx",
+    "third_party/libpng",
 ]
 
 ################################################################################
@@ -547,15 +551,17 @@ COPTS_ALL = []
 ################################################################################
 
 DEFINES_UNIX = [
-    "PNG_SKIP_SETJMP_CHECK",
     "SK_BUILD_FOR_UNIX",
     "SK_SAMPLES_FOR_X",
     "SK_SFNTLY_SUBSETTER",
     "SK_CODEC_DECODES_RAW",
     "SK_HAS_GIF_LIBRARY",
     "SK_HAS_JPEG_LIBRARY",
-    "SK_HAS_PNG_LIBRARY",
     "SK_HAS_WEBP_LIBRARY",
+    "SK_HAS_PNG_LIBRARY",
+    "PNG_ARM_NEON_OPT=0",
+    "PNG_INTEL_SSE_OPT=0",
+    "PNG_ARM_NEON_IMPLEMENTATION=0",
 ]
 
 DEFINES_ANDROID = [
@@ -563,8 +569,11 @@ DEFINES_ANDROID = [
     "SK_CODEC_DECODES_RAW",
     "SK_HAS_GIF_LIBRARY",
     "SK_HAS_JPEG_LIBRARY",
-    "SK_HAS_PNG_LIBRARY",
     "SK_HAS_WEBP_LIBRARY",
+    "SK_HAS_PNG_LIBRARY",
+    "PNG_ARM_NEON_OPT=0",
+    "PNG_INTEL_SSE_OPT=0",
+    "PNG_ARM_NEON_IMPLEMENTATION=0",
 ]
 
 DEFINES_IOS = [