Add Linux kernel event handling code

This is a simple handler for uevents send by the Linux
kernel.

CMakeLists.txt

@@ -7,6 +7,9 @@ option( ENABLE_EXAMPLES "Install additional tin2rc examples" ON )
 option( ENABLE_RSVG "Rsvg support (launcher only)" ON )
 option( ENABLE_SN "Startup notification support" ON )
 option( ENABLE_ASAN "Build tint2 with AddressSanitizer" OFF )
+if( CMAKE_SYSTEM_NAME STREQUAL "Linux" )
+  option( ENABLE_UEVENT "Kernel event handling support" ON )
+endif( CMAKE_SYSTEM_NAME STREQUAL "Linux" )
 
 include( FindPkgConfig )
 include( CheckLibraryExists )
@@ -111,6 +114,11 @@ if( ENABLE_SN )
   endif( SN_FOUND )
 endif( ENABLE_SN)
 
+if( ENABLE_UEVENT )
+  add_definitions( -DENABLE_UEVENT )
+  set( SOURCES ${SOURCES} src/util/uevent.c)
+endif( ENABLE_UEVENT )
+
 if( ENABLE_TINT2CONF )
   add_definitions( -DHAVE_VERSION_H )
   add_subdirectory( src/tint2conf )