[CMake] Simple dependency scanner, aka GET_SOURCE_FILE_PROPERTY +INCLUDE_DIRECTORIES

[Mathieu Malaterre]

Hello,

  I have written a very simple dependencie scanner (*). It works for
the limited usage that I have, except for one case. Let say my swig
file is:

%module FooBar
%{
#include "MyModule1.h"
#include "MyModule2.h"
#include "Python.h"
%}

Assuming the files MyModule1.h and MyModule2.h can be found by
GET_SOURCE_FILE_PROPERTY, but Python.h cannot. Is there a way to tell
GET_SOURCE_FILE_PROPERTY to use
GET_DIRECTORY_PROPERTY#INCLUDE_DIRECTORIES to figure out where
Python.h is ?

Thanks
-Mathieu
Ps: No I cannot use swig -MM option

(*)
MACRO(SWIG_GET_DEP SWIG_FILE)
  # Read the swig file:
  FILE(READ ${SWIG_FILE} swig_file)
  # STRING MATCHALL does not work, thus do a line by line STRING MATCH
  STRING(REGEX REPLACE "\r?\n" ";" ENT "${swig_file}")

  FOREACH(line ${ENT})
    STRING(REGEX MATCH "^[ ]*[%|#]include.*$" out1 ${line})
    # REGEX REPLACE is ALWAYS called, thus producing garbage most of
the time. Need to couple it with
    # REPLACE MATCH
    STRING(REGEX REPLACE "^[ ]*[%|#]include[ \"]*([^\"]+)[ \"]*$"
"\\1" out ${line})
    IF( out1 )
      IF( ${out} MATCHES ".*\\.h$" )
        GET_SOURCE_FILE_PROPERTY(var ${out} LOCATION)
        IF(EXISTS ${var} )
          MESSAGE( "DEP: ${out}" )
        ENDIF(EXISTS ${var} )
      ENDIF( ${out} MATCHES ".*\\.h$" )
    ENDIF( out1 )
  ENDFOREACH(line)
ENDMACRO(SWIG_GET_DEP)