Fix license header on patch + add CMake condition for AWS patch

ci/rtools/BuildAwsCCommon.patch

@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 diff --git a/cmake/AwsCFlags.cmake b/cmake/AwsCFlags.cmake
 index b717bca..5aa8ac9 100644
 --- a/cmake/AwsCFlags.cmake

cpp/cmake_modules/ThirdpartyToolchain.cmake

@@ -5046,10 +5046,7 @@ macro(build_awssdk)
 
   # WIP GH-44950
   # Patch parts of the AWSSDK EP so it builds cleanly under Rtools40
-  if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
-    message(STATUS "############ On Windows")
-    message(STATUS "############ Using Windows compiler: ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER}"
-    )
+  if(WIN32 AND NOT MSVC)
     find_program(PATCH patch REQUIRED)
     # Patch aws_c_common to build under Rtools40
     set(AWS_C_COMMON_PATCH_COMMAND ${PATCH} -p1 -i