[android] fix pthread flag inclusion in libxml2 package

Author: hyp

CMakeLists.txt

@@ -150,6 +150,12 @@ if(NOT CMAKE_SYSTEM_NAME STREQUAL "WASI")
             "-I${DISPATCH_INCLUDE_PATH}/Block")
     endif()
 endif()
+if(ANDROID)
+  # LibXml2 looks for the Threads package, so
+  # ensure that it doesn't try to use the `-pthread`
+  # flag on Android.
+  set(CMAKE_HAVE_LIBC_PTHREAD YES)
+endif()
 find_package(LibXml2 REQUIRED)
 if(FOUNDATION_BUILD_NETWORKING)
     find_package(CURL REQUIRED)