put all aws_key_management plugin files into plugin/aws_key_management

that is, download AWS SDK there, not into the builddir root.
and .gitignore them all.

.gitignore

@@ -91,6 +91,9 @@ pcre/pcre_chartables.c
 pcre/pcregrep
 pcre/pcretest
 pcre/test*grep
+plugin/aws_key_management/aws-sdk-cpp
+plugin/aws_key_management/aws_sdk_cpp
+plugin/aws_key_management/aws_sdk_cpp-prefix
 scripts/comp_sql
 scripts/make_binary_distribution
 scripts/msql2mysql

plugin/aws_key_management/CMakeLists.txt

@@ -108,7 +108,7 @@ ELSE()
     GIT_REPOSITORY "https://github.com/awslabs/aws-sdk-cpp.git"
     GIT_TAG "1.0.8"
     UPDATE_COMMAND ""
-    SOURCE_DIR "${CMAKE_BINARY_DIR}/aws-sdk-cpp"
+    SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/aws-sdk-cpp"
     CMAKE_ARGS 
     -DBUILD_ONLY=kms
     -DBUILD_SHARED_LIBS=OFF
@@ -118,7 +118,7 @@ ELSE()
     "-DCMAKE_CXX_FLAGS_RELEASE=${CMAKE_CXX_FLAGS_RELEASE} ${PIC_FLAG}"
     "-DCMAKE_CXX_FLAGS_MINSIZEREL=${CMAKE_CXX_FLAGS_MINSIZEREL} ${PIC_FLAG}"
     ${EXTRA_SDK_CMAKE_FLAGS}
-    -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/aws_sdk_cpp
+    -DCMAKE_INSTALL_PREFIX=${CMAKE_CURRENT_BINARY_DIR}/aws_sdk_cpp
     TEST_COMMAND ""
   )
   SET_TARGET_PROPERTIES(aws_sdk_cpp PROPERTIES EXCLUDE_FROM_ALL TRUE)
@@ -127,7 +127,7 @@ ELSE()
   FOREACH(lib ${AWS_SDK_LIBS})
     ADD_LIBRARY(${lib} STATIC IMPORTED GLOBAL)
     ADD_DEPENDENCIES(${lib} aws_sdk_cpp)
-    SET(loc "${CMAKE_BINARY_DIR}/aws_sdk_cpp/lib/${CMAKE_STATIC_LIBRARY_PREFIX}${lib}${CMAKE_STATIC_LIBRARY_SUFFIX}")
+    SET(loc "${CMAKE_CURRENT_BINARY_DIR}/aws_sdk_cpp/lib/${CMAKE_STATIC_LIBRARY_PREFIX}${lib}${CMAKE_STATIC_LIBRARY_SUFFIX}")
     SET_TARGET_PROPERTIES(${lib} PROPERTIES IMPORTED_LOCATION ${loc})
   ENDFOREACH()
 
@@ -136,7 +136,7 @@ ELSE()
     SET(AWS_SDK_LIBS -Wl,--whole-archive ${AWS_SDK_LIBS} -Wl,--no-whole-archive)
   ENDIF()
   SET_TARGET_PROPERTIES(aws_sdk_cpp PROPERTIES EXCLUDE_FROM_ALL TRUE)
-  INCLUDE_DIRECTORIES(${CMAKE_BINARY_DIR}/aws_sdk_cpp/include)
+  INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR}/aws_sdk_cpp/include)
 ENDIF()
 
 ADD_DEFINITIONS(${SSL_DEFINES}) # Need to know whether openssl should be initialized