diff --git a/lldb/tools/driver/CMakeLists.txt b/lldb/tools/driver/CMakeLists.txt
index cd304a047dea6..89884ecd0601b 100644
--- a/lldb/tools/driver/CMakeLists.txt
+++ b/lldb/tools/driver/CMakeLists.txt
@@ -11,6 +11,11 @@ if(APPLE)
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-sectcreate,__TEXT,__info_plist,${CMAKE_CURRENT_BINARY_DIR}/lldb-Info.plist")
 endif()
 
+if (UNIX AND ${CMAKE_SYSTEM_NAME} MATCHES "AIX")                               
+  remove_definitions("-D_XOPEN_SOURCE=700")                                    
+  add_definitions("-D_ALL_SOURCE")                                             
+endif()
+
 add_lldb_tool(lldb
   Driver.cpp
   Platform.cpp