Strict aliasing rule in C++11

I use the following C structs in my C++11 code (the code comes from liblwgeom of PostGis, but this is not the core of the question). The code is compiled with the following options using g++-4.8:

-std=c++11 -Wall -Wextra -pedantic-errors -pedantic -Werror

and I don't get any errors during compilation (or warnings) (should I get any?)

POLYGON:

typedef struct
{
        uint8_t type; /* POLYGONTYPE */
        uint8_t flags;
        GBOX *bbox;
        int32_t srid;
        int nrings;   /* how many rings we are currently storing */
        int maxrings; /* how many rings we have space for in **rings */
        POINTARRAY **rings; /* list of rings (list of points) */
}
LWPOLY; /* "light-weight polygon" */

LWGEOM:

typedef struct
{
        uint8_t type;
        uint8_t flags;
        GBOX *bbox;
        int32_t srid;
        void *data;
}
LWGEOM;

POINTARRAY:

typedef struct
{
        /* Array of POINT 2D, 3D or 4D, possibly missaligned. */
        uint8_t *serialized_pointlist;

        /* Use FLAGS_* macros to handle */
        uint8_t  flags;

        int npoints;   /* how many points we are currently storing */
        int maxpoints; /* how many points we have space for in serialized_pointlist */
}
POINTARRAY;

GBOX:

typedef struct
{
        uint8_t flags;
        double xmin;
        double xmax;
        double ymin;
        double ymax;
        double zmin;
        double zmax;
        double mmin;
        double mmax;
} GBOX;

Am I violating strict aliasing rule when I do something like?

const LWGEOM* lwgeom;
...
const LWPOLY* lwpoly = reinterpret_cast<const LWPOLY*>(lwgeom);

I know that in PostGis types are specifically designed to be "compatible" however I'd like to know if I am violating the standard by doing so.

Also, I noticed that PostGis is not compiled with strict aliasing disabled by default (at least version 2.1.5).