fix if comparison with uninitialized member value

Fix the valgrind warning from the use of an uninitialized
member variable by setting the DEFAULT value for
m_currentNativeCursor in the constructors member initializer list.
This fixes the following warning caused by the SetNativeCursorStyle
method call later on the constructor.

==66660== Warning: client switching stacks?  SP change: 0x1ffeffee40 --> 0xdf7efe8
==66660==          to suppress, use: --max-stackframe=137187819096 or greater
==66660== Conditional jump or move depends on uninitialised value(s)
==66660==    at 0x13F0764E: UnknownInlinedFun (graphics_abstraction_layer.cpp:276)
==66660==    by 0x13F0764E: KIGFX::GAL::GAL(KIGFX::GAL_DISPLAY_OPTIONS&) (graphics_abstraction_layer.cpp:78)

Error can be reproduced and checked from the log.txt
by launching kicad with valgrind command
"valgrind --leak-check=full kicad > log.txt 2>&1"
and then launching the footprint editor from the kicad main dialog.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/8784

Signed-off-by: Mika Laitio <lamikr@gmail.com>

common/gal/graphics_abstraction_layer.cpp

@@ -38,7 +38,13 @@ using namespace KIGFX;
 
 GAL::GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions ) :
         m_options( aDisplayOptions ),
-        m_strokeFont( this )
+        m_strokeFont( this ),
+        // m_currentNativeCursor is initialized with KICURSOR::DEFAULT value to avoid
+        // if comparison with uninitialized value on SetNativeCursorStyle method.
+        // Some classes inheriting from GAL has different SetNativeCursorStyle method
+        // implementation and therefore it's called also on constructor
+        // to change the value from DEFAULT to KICURSOR::ARROW
+        m_currentNativeCursor( KICURSOR::DEFAULT )
 {
     // Set the default values for the internal variables
     SetIsFill( false );