diff --git a/api/gutil.cpp b/api/gutil.C
similarity index 100%
rename from api/gutil.cpp
rename to api/gutil.C
diff --git a/api/mac_app_opengl.cpp b/api/mac_app_opengl.C
similarity index 100%
rename from api/mac_app_opengl.cpp
rename to api/mac_app_opengl.C
diff --git a/api/mac_carbon_gl.cpp b/api/mac_carbon_gl.C
similarity index 100%
rename from api/mac_carbon_gl.cpp
rename to api/mac_carbon_gl.C
diff --git a/api/reduce.cpp b/api/reduce.C
similarity index 100%
rename from api/reduce.cpp
rename to api/reduce.C
diff --git a/api/windows_opengl.cpp b/api/windows_opengl.C
similarity index 100%
rename from api/windows_opengl.cpp
rename to api/windows_opengl.C