likscan: Prefer pkg-config for libsane detection

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

libkscan/ConfigureChecks.cmake

@@ -9,10 +9,13 @@
 #
 #################################################
 
-if( NOT HAVE_SANE )
-  message( STATUS "checking for 'sane'..." )
+if( NOT SANE_FOUND )
+  pkg_search_module( SANE sane-backends )
 endif( )
 
+if( NOT SANE_FOUND )
+  message( STATUS "checking for 'sane'..." )
+
   # find sane-config
   find_program( SANE_EXECUTABLE NAMES sane-config )
   if( NOT SANE_EXECUTABLE )
@@ -37,6 +40,8 @@ __run_sane_config( libs SANE_LIBRARIES )
   # cleanup
   if( SANE_INCLUDE_DIRS )
     string( REGEX REPLACE "(^| )-I" ";" SANE_INCLUDE_DIRS "${SANE_INCLUDE_DIRS}" )
+  else( )
+    set( SANE_INCLUDE_DIRS "/usr/include" )
   endif( )
   if( SANE_LIBRARIES )
     ## remove all spaces and replace whitespace with ';'
@@ -48,7 +53,10 @@ if( SANE_LIBRARIES )
     ## remove '-l'
     string( REGEX REPLACE "-l" "" SANE_LIBRARIES "${SANE_LIBRARIES}" )
   endif( )
-
-if( NOT HAVE_SANE )
   message( STATUS "  found 'sane', version ${SANE_VERSION}" )
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args( SANE DEFAULT_MSG
+                                     SANE_LIBRARIES
+                                     SANE_INCLUDE_DIRS )
 endif( )