Install SWIG interface definition to the include directory, so outside plugins...

Install SWIG interface definition to the include directory, so outside plugins can use it when building their Python APIs

wrappers/python/CMakeLists.txt

@@ -106,7 +106,7 @@ mark_as_advanced(CLEAR DOXYGEN_EXECUTABLE)
 set(SWIG_OPENMM_DIR "${OPENMM_PYTHON_STAGING_DIR}/src/swig_doxygen")
 file(MAKE_DIRECTORY ${SWIG_OPENMM_DIR}/swig_lib/python)
 
-### Create OpenMM_headers.xml ###
+### Create OpenMMSwigHeaders.i ###
 # Step 1 - Create Doxyfile to point to OpenMM headers
 configure_file(
     ${CMAKE_CURRENT_SOURCE_DIR}/src/swig_doxygen/doxygen/Doxyfile.in
@@ -130,7 +130,7 @@ set(SWIG_INPUT_FILES_REF
     "${SWIG_OPENMM_DIR}/swig_lib/python/pythonprepend.i"
     "${SWIG_OPENMM_DIR}/swig_lib/python/pythonappend.i"
     "${SWIG_OPENMM_DIR}/OpenMM_docstring.i"
-    "${SWIG_OPENMM_DIR}/OpenMM_headers.i"
+    "${SWIG_OPENMM_DIR}/OpenMMSwigHeaders.i"
     # "${SWIG_OPENMM_DIR}/OpenMM.i"
 )
 
@@ -153,7 +153,7 @@ add_custom_command(
         -i "${CMAKE_CURRENT_BINARY_DIR}/src/swig_doxygen/doxygen/xml"
         -c swigInputConfig.py
         -d OpenMM_docstring.i
-        -o OpenMM_headers.i
+        -o OpenMMSwigHeaders.i
         -a swig_lib/python/pythonprepend.i
         -z swig_lib/python/pythonappend.i
     WORKING_DIRECTORY "${SWIG_OPENMM_DIR}"
@@ -164,6 +164,8 @@ add_custom_command(
     COMMENT "Creating OpenMM Python swig input files..."
 )
 
+INSTALL_FILES(/include FILES "${SWIG_OPENMM_DIR}/OpenMMSwigHeaders.i")
+
 #~ swig -python -c++ \
 #~      -outdir $PYTHON_PACKAGE_DIR \
 #~      -o OpenMMSwig.cxx \