Fixed external SMESH cmake scripts, allowing netgen and gmsh compatibility with VTK 9

- moved base SMESH cmake logic to respective cmake script.
- allow BUILD_SMESH, regardless of external SMESH usage, for testing and so on.

cMake/FindSMESH.cmake

@@ -5,28 +5,55 @@
 # SMESH_INCLUDE_DIR   - where the Salome SMESH include directory can be found
 # SMESH_LIBRARIES     - Link this to use Salome SMESH
 #
- 
 
+# SMESH needs VTK
+find_package(VTK REQUIRED)
+
+# If this definition is not set, linker errors will occur against SMESH on 64 bit machines.
+if(CMAKE_SIZEOF_VOID_P STREQUAL 8)
+	add_definitions(-DSALOME_USE_64BIT_IDS)
+endif(CMAKE_SIZEOF_VOID_P STREQUAL 8)
+ 
 IF (CMAKE_COMPILER_IS_GNUCC)
     FIND_PATH(SMESH_INCLUDE_DIR SMESH_Mesh.hxx
     # These are default search paths, why specify them?
-    # /usr/include
-    # /usr/local/include
-    PATH_SUFFIXES smesh
-    )
-    FIND_LIBRARY(SMESH_LIBRARY SMESH
-    #  /usr/lib
-    #  /usr/local/lib
+    PATH_SUFFIXES smesh SMESH smesh/SMESH
     )
+    FIND_LIBRARY(SMESH_LIBRARY SMESH)
 ELSE (CMAKE_COMPILER_IS_GNUCC)
     # Not yet implemented
 ENDIF (CMAKE_COMPILER_IS_GNUCC)
 
+IF(SMESH_INCLUDE_DIR)
+	SET(SMESH_INC_ROOT "${SMESH_INCLUDE_DIR}/..")
+	# Append extra include dirs
+	SET(SMESH_INCLUDE_DIR 
+	"${SMESH_INCLUDE_DIR};
+	${SMESH_INC_ROOT}/Controls;
+	${SMESH_INC_ROOT}/Driver;
+	${SMESH_INC_ROOT}/DriverDAT;
+	${SMESH_INC_ROOT}/DriverGMF;
+	${SMESH_INC_ROOT}/DriverSTL;
+	${SMESH_INC_ROOT}/DriverUNV;
+	${SMESH_INC_ROOT}/Geom;
+	${SMESH_INC_ROOT}/Kernel;
+	${SMESH_INC_ROOT}/MEFISTO2;
+	${SMESH_INC_ROOT}/MeshVSLink;
+	${SMESH_INC_ROOT}/Netgen;
+	${SMESH_INC_ROOT}/NETGENPlugin;
+	${SMESH_INC_ROOT}/SMDS;
+	${SMESH_INC_ROOT}/SMESHDS;
+	${SMESH_INC_ROOT}/SMESHUtils;
+	${SMESH_INC_ROOT}/StdMeshers;")
+ELSE(SMESH_INCLUDE_DIR)
+	message(FATAL_ERROR "SMESH include directories not found!")
+ENDIF(SMESH_INCLUDE_DIR)
+
 SET(SMESH_FOUND FALSE)
 IF(SMESH_LIBRARY)
   SET(SMESH_FOUND TRUE)
   GET_FILENAME_COMPONENT(SMESH_LIBRARY_DIR ${SMESH_LIBRARY} PATH)
-  set(SMESH_LIBRARIES
+  set(SMESH_LIBRARIES 
     ${SMESH_LIBRARY_DIR}/libDriver.so
     ${SMESH_LIBRARY_DIR}/libDriverDAT.so
     ${SMESH_LIBRARY_DIR}/libDriverSTL.so
@@ -36,5 +63,8 @@ IF(SMESH_LIBRARY)
     ${SMESH_LIBRARY_DIR}/libSMESHDS.so
     ${SMESH_LIBRARY_DIR}/libStdMeshers.so
   )
+  set(EXTERNAL_SMESH_LIBS ${SMESH_LIBRARIES})
+ELSE(SMESH_LIBRARY)
+	message(FATAL_ERROR "SMESH libraries NOT FOUND!")
 ENDIF(SMESH_LIBRARY)
 

cMake/FreeCAD_Helpers/SetupSalomeSMESH.cmake

@@ -1,6 +1,10 @@
 macro(SetupSalomeSMESH)
 # -------------------------------- Salome SMESH --------------------------
 
+    # Allow using external SMESH
+    if (FREECAD_USE_EXTERNAL_SMESH)
+        find_package(SMESH REQUIRED)
+    endif(FREECAD_USE_EXTERNAL_SMESH)
     # Salome SMESH sources are under src/3rdParty now
     if(BUILD_SMESH)
         # set the internal smesh version: