fix libpng

Author: Totto16

subprojects/libpng.wrap

@@ -8,5 +8,7 @@ patch_url = https://wrapdb.mesonbuild.com/v2/libpng_1.6.39-2/get_patch
 patch_hash = 8bcf8f69f50233f3a35e3718ab3c91b0c51b4c1a08a84c87be0b1f4813adf17f
 wrapdb_version = 1.6.39-2
 
+diff_files = libpng-1.6.39_web.diff
+
 [provide]
 libpng = libpng_dep

subprojects/packagefiles/libpng-1.6.39_web.diff

@@ -0,0 +1,14 @@
+diff --git a/meson.build b/meson.build
+index a57347c..03272e1 100644
+--- a/meson.build
++++ b/meson.build
+@@ -83,6 +83,9 @@ elif host_machine.cpu_family() in ['x86', 'x86_64']
+     'intel/intel_init.c',
+   )
+   c_args += '-DPNG_INTEL_SSE_OPT=1'
++elif host_machine.system() == 'emscripten'
++    thread_dep = dependency('threads')
++    libpng_deps += thread_dep
+ endif
+ 
+ libpng = library(