[fix](build) stop building libhdfspp on macOS

hadoop-hdfs-project/hadoop-hdfs-native-client/src/CMakeLists.txt

@@ -204,12 +204,11 @@ check_cxx_source_compiles(
     }"
     THREAD_LOCAL_SUPPORTED)
 if (APPLE)
-    # libhdfspp's shared library links the static libsasl2 found under the Doris thirdparty
-    # prefix, whose GSSAPI plugin leaves gss_* undefined. Linux' ld tolerates undefined
-    # symbols in a .so; macOS' ld does not, so the dylib fails to link and takes the whole
-    # make down with it - libhdfs.a included. SASL is used by libhdfspp alone, which Doris
-    # never links (be/CMakeLists.txt sets BUILD_LIBHDFSPP OFF), so turn it off through the
-    # escape hatch libhdfspp/CMakeLists.txt documents.
+    # macOS stops after the x-platform object libraries libhdfs needs and never builds
+    # libhdfspp itself - see main/native/libhdfspp/CMakeLists.txt for why.  SASL has no other
+    # consumer, so skip looking for it through the escape hatch that file documents; the
+    # static libsasl2 under the Doris thirdparty prefix would not link here anyway, its
+    # GSSAPI plugin leaves gss_* undefined and macOS' ld, unlike Linux', rejects that.
     set(NO_SASL 1)
 endif()
 if (THREAD_LOCAL_SUPPORTED)

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/CMakeLists.txt

@@ -259,6 +259,21 @@ include_directories( SYSTEM
   ${PROTOBUF_INCLUDE_DIRS}
 )
 
+# Doris never links libhdfspp - be/CMakeLists.txt sets BUILD_LIBHDFSPP OFF - and on macOS the
+# library cannot be linked at all.  It is compiled against Homebrew LLVM's libc++ headers, which
+# are configured without Apple's availability annotations, so std::exception_ptr's post-macOS-14
+# entry points (__cxa_init_primary_exception, exception_ptr::__from_native_exception_pointer) are
+# emitted whatever -mmacosx-version-min says, while -lc++ still resolves against the SDK's system
+# libc++.  Against a macOS 14 SDK those two symbols are missing, libhdfspp.dylib fails to link,
+# and it takes the whole make down with it - libhdfs.a included.
+#
+# libhdfs does need the x-platform object libraries out of this tree, so build those and stop
+# there.  Every compile setting they depend on is already in place above this point.
+if(APPLE)
+    add_subdirectory(lib/x-platform)
+    return()
+endif()
+
 add_subdirectory(third_party/uriparser2)
 add_subdirectory(lib)
 if(NOT HDFSPP_LIBRARY_ONLY)