Configure and install thumbnailer

Currently the file "src/XDGData/FreeCAD.thumbnailer" gets installed, but
the associated freecad-thumbnailer script isn't. Install the script,
too.

While here, have the paths to the default icon and freecad-thumbnailer
script follow ${CMAKE_INSTALL_DATAROOTDIR} and ${CMAKE_INSTALL_BINDIR}
respectively.

src/XDGData/CMakeLists.txt

@@ -30,7 +30,20 @@ install(
     DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/mime/packages
 )
 
+configure_file(
+    FreeCAD.thumbnailer.in
+    ${CMAKE_BINARY_DIR}/FreeCAD.thumbnailer
+)
 install(
-    FILES FreeCAD.thumbnailer
+    FILES ${CMAKE_BINARY_DIR}/FreeCAD.thumbnailer
     DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/thumbnailers
 )
+
+configure_file(
+    ${CMAKE_SOURCE_DIR}/src/Tools/freecad-thumbnailer.in
+    ${CMAKE_BINARY_DIR}/freecad-thumbnailer
+)
+install(
+    PROGRAMS ${CMAKE_BINARY_DIR}/freecad-thumbnailer
+    TYPE BIN
+)

src/XDGData/FreeCAD.thumbnailer

@@ -1,4 +0,0 @@
-[Thumbnailer Entry]
-TryExec=freecad-thumbnailer
-Exec=freecad-thumbnailer -s %s %i %o
-MimeType=application/x-extension-fcstd;

src/XDGData/FreeCAD.thumbnailer.in

@@ -0,0 +1,4 @@
+[Thumbnailer Entry]
+TryExec=@CMAKE_INSTALL_BINDIR@/freecad-thumbnailer
+Exec=@CMAKE_INSTALL_BINDIR@/freecad-thumbnailer -s %s %i %o
+MimeType=application/x-extension-fcstd;