pysics.box2d.library: Add "-O2" flags to compile switches.

3-mid/physics/implement/box2d/library/box2d_contrib.gpr

@@ -21,7 +21,9 @@ is
    end Naming;
 
    package Compiler is
-      for Default_Switches ("c++") use ("-g", "-I../../contrib/include");
+      for Default_Switches ("c++") use ("-g",
+                                        "-O2",
+                                        "-I../../contrib/include");
    end Compiler;
 
 end Box2d_contrib;

3-mid/physics/implement/box2d/library/box2d_thin_c.gpr

@@ -23,7 +23,8 @@ is
    package Binder  renames Lace_shared.Binder;
 
    package Compiler is
-      for Default_Switches ("c++") use ("-g", 
+      for Default_Switches ("c++") use ("-g",
+                                        "-O2",
                                         "-Wno-return-type-c-linkage",
                                         "-I../../../c_math/source/c",
                                         "-I../../contrib/include");

3-mid/physics/implement/box2d/library/box2d_thin_cxx.gpr

@@ -22,7 +22,8 @@ is
    end Naming;
 
    package Compiler is
-      for Default_Switches ("c++") use ("-g", 
+      for Default_Switches ("c++") use ("-g",
+                                        "-O2",
                                         "-fPIC",
                                         "-I../../../c_math/source/c",
                                         "-Wno-return-type-c-linkage");