Reintroduce C++ support and add usage tests for C++ (#4)

Reviewed-on: #4
Co-authored-by: Abdelrahman <said.abdelrahman89@gmail.com>
Co-committed-by: Abdelrahman <said.abdelrahman89@gmail.com>

src/core/mem/arena/mem_arena.h

@@ -8,6 +8,10 @@
 #include "../../os/mem/mem_os.h"
 #include <stdbool.h>
 
+#ifdef WAPP_PLATFORM_CPP
+BEGIN_C_LINKAGE
+#endif // !WAPP_PLATFORM_CPP
+
 typedef struct arena Arena;
 
 #define wapp_mem_arena_init(arena_dptr, base_capacity)                         \
@@ -32,4 +36,8 @@ void *wapp_mem_arena_realloc_aligned(Arena *arena, void *ptr, u64 old_size, u64
 void wapp_mem_arena_clear(Arena *arena);
 void wapp_mem_arena_destroy(Arena **arena);
 
+#ifdef WAPP_PLATFORM_CPP
+END_C_LINKAGE
+#endif // !WAPP_PLATFORM_CPP
+
 #endif // !MEM_ARENA_H