Add arrow patch, to fix inclusion of emscripten.h within extern C in xxhash.

Author: carlopi

Makefile

@@ -435,6 +435,7 @@ build/docker_ci_image:
 
 patch_duckdb:
 	find patches/duckdb/* -type f -name '*.patch' -print0 | xargs -0 cat | patch -p1 --forward -d submodules/duckdb
+	find patches/arrow/* -type f -name '*.patch' -print0 | xargs -0 cat | patch -p1 --forward -d submodules/arrow
 
 submodules:
 	git submodule update --init --recursive

patches/arrow/hashing_compile_in_emscripten.patch

@@ -0,0 +1,15 @@
+diff --git a/cpp/src/arrow/util/hashing.h b/cpp/src/arrow/util/hashing.h
+index 2de9f41532..1a7803d2d8 100644
+--- a/cpp/src/arrow/util/hashing.h
++++ b/cpp/src/arrow/util/hashing.h
+@@ -31,6 +31,10 @@
+ #include <utility>
+ #include <vector>
+ 
++#ifdef EMSCRIPTEN
++#include <emscripten.h>
++#endif
++
+ #include "arrow/array/builder_binary.h"
+ #include "arrow/buffer_builder.h"
+ #include "arrow/result.h"