Doxyfile.in: use basedir insert

docs/Doxyfile.in

@@ -829,7 +829,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = model/src
+INPUT                  = @SRC_BASEDIR@/model/src
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
@@ -2285,7 +2285,7 @@ CLASS_DIAGRAMS         = NO
 # DIA_PATH tag allows you to specify the directory where the dia binary resides.
 # If left empty dia is assumed to be found in the default search path.
 
-DIA_PATH               = 
+DIA_PATH               =
 
 # If set to YES the inheritance and collaboration graphs will hide inheritance
 # and usage relations if the target is undocumented or is not a class.