diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2361e630c..3f9c96b1d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,11 @@
 PROJECT(CMake)
 
+IF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+  IF(NOT CMAKE_COMPILER_IS_GNUCXX)
+     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -tweak -no_implicit_include ")
+  ENDIF(NOT CMAKE_COMPILER_IS_GNUCXX)
+ENDIF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+
 SUBDIRS(Source Modules Templates Utilities)
 ENABLE_TESTING()
 
diff --git a/Tests/Complex/CMakeLists.txt b/Tests/Complex/CMakeLists.txt
index 58a128123..9eefd8b1e 100644
--- a/Tests/Complex/CMakeLists.txt
+++ b/Tests/Complex/CMakeLists.txt
@@ -12,6 +12,13 @@ IF (CMAKE_ANSI_CXXFLAGS)
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_ANSI_CXXFLAGS}")  
 ENDIF (CMAKE_ANSI_CXXFLAGS)
 
+IF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+  IF(NOT CMAKE_COMPILER_IS_GNUCXX)
+     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -tweak -no_implicit_include ")
+  ENDIF(NOT CMAKE_COMPILER_IS_GNUCXX)
+ENDIF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+
+
 ADD_DEFINITIONS(-DCMAKE_IS_FUN)
 
 SET(TEST_SEP "a b c")
diff --git a/Tests/ComplexOneConfig/CMakeLists.txt b/Tests/ComplexOneConfig/CMakeLists.txt
index 58a128123..9eefd8b1e 100644
--- a/Tests/ComplexOneConfig/CMakeLists.txt
+++ b/Tests/ComplexOneConfig/CMakeLists.txt
@@ -12,6 +12,13 @@ IF (CMAKE_ANSI_CXXFLAGS)
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_ANSI_CXXFLAGS}")  
 ENDIF (CMAKE_ANSI_CXXFLAGS)
 
+IF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+  IF(NOT CMAKE_COMPILER_IS_GNUCXX)
+     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -tweak -no_implicit_include ")
+  ENDIF(NOT CMAKE_COMPILER_IS_GNUCXX)
+ENDIF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+
+
 ADD_DEFINITIONS(-DCMAKE_IS_FUN)
 
 SET(TEST_SEP "a b c")
diff --git a/Tests/ComplexRelativePaths/CMakeLists.txt b/Tests/ComplexRelativePaths/CMakeLists.txt
index 58a128123..9eefd8b1e 100644
--- a/Tests/ComplexRelativePaths/CMakeLists.txt
+++ b/Tests/ComplexRelativePaths/CMakeLists.txt
@@ -12,6 +12,13 @@ IF (CMAKE_ANSI_CXXFLAGS)
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_ANSI_CXXFLAGS}")  
 ENDIF (CMAKE_ANSI_CXXFLAGS)
 
+IF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+  IF(NOT CMAKE_COMPILER_IS_GNUCXX)
+     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -tweak -no_implicit_include ")
+  ENDIF(NOT CMAKE_COMPILER_IS_GNUCXX)
+ENDIF(CMAKE_SYSTEM MATCHES "OSF1-V.*")
+
+
 ADD_DEFINITIONS(-DCMAKE_IS_FUN)
 
 SET(TEST_SEP "a b c")