Fix test compilation on MacOS

src/tests/bitmath_func.cpp

@@ -7,6 +7,7 @@
 
 /** @file bitmath_func_test.cpp Test functionality from core/bitmath_func. */
 
+#define OPENTTD_TEST
 #include "../stdafx.h"
 
 #include "../3rdparty/catch2/catch.hpp"

src/tests/landscape_partial_pixel_z.cpp

@@ -7,6 +7,7 @@
 
 /** @file landscape_partial_pixel_z.cpp Tests for consistency/validity of the results of GetPartialPixelZ. */
 
+#define OPENTTD_TEST
 #include "../stdafx.h"
 
 #include "../3rdparty/catch2/catch.hpp"

src/tests/math_func.cpp

@@ -7,6 +7,7 @@
 
 /** @file math_func_test.cpp Test functionality from core/math_func. */
 
+#define OPENTTD_TEST
 #include "../stdafx.h"
 
 #include "../3rdparty/catch2/catch.hpp"

src/tests/ring_buffer.cpp

@@ -7,6 +7,7 @@
 
 /** @file ring_buffer.cpp Test functionality from core/ring_buffer.hpp */
 
+#define OPENTTD_TEST
 #include "../stdafx.h"
 
 #include "../3rdparty/catch2/catch.hpp"

src/tests/test_main.cpp

@@ -7,6 +7,7 @@
 
 /** @file test_main.cpp Entry point for all the unit tests. */
 
+#define OPENTTD_TEST
 #include "../stdafx.h"
 
 #include <stdarg.h>