Possible alignment issues reported by -fsanitize=undefined

Compiling with the flag -fsanitize=undefined and running the EAGLE_6 test, we get the following warnings:

runner.c:1863:13: runtime error: member access within misaligned address 0x000001cdda20 for type 'struct runner', which requires 64 byte alignment
0x000001cdda20: note: pointer points here
 00 00 00 00  00 00 00 00 d9 2a 00 00  00 07 10 ac d9 2a 00 00  00 00 00 00 00 00 00 00  b0 25 04 a5
              ^ 
runner.c:346:43: runtime error: member access within misaligned address 0x000001ce1e60 for type 'struct runner', which requires 64 byte alignment
0x000001ce1e60: note: pointer points here
 00 00 00 00  0d 00 00 00 00 00 00 00  00 c7 d0 ad d9 2a 00 00  0d 00 00 00 0d 00 00 00  b0 25 04 a5
              ^ 
gravity_cache.h:79:8: runtime error: member access within misaligned address 0x0000028faa60 for type 'struct gravity_cache', which requires 64 byte alignment
0x0000028faa60: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^ 
gravity_cache.h:91:12: runtime error: member access within misaligned address 0x0000028faa60 for type 'struct gravity_cache', which requires 64 byte alignment
0x0000028faa60: note: pointer points here
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^ 
gravity_cache.h:129:12: runtime error: member access within misaligned address 0x0000028faa60 for type 'struct gravity_cache', which requires 64 byte alignment
0x0000028faa60: note: pointer points here
 00 00 00 00  c0 c8 9d 02 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00

and many others. Not sure quite what is complaining about. Using GCC 5.4.