ignore_case_chain, cartoon_gap_cutoff, ...
large number of -Wwritable-strings warnings at r4147 under Apple clang 7.2
silenced by re-adding -Wno-write-strings (svn rev 4148)
byring, distance mode=4, cartoon dash, ...
contrib/champ/os_memory.c produces while loop has empty body warnings
should be fixed in SVN rev 4147
pymol r4146 needs addition patches to contrib/champ/os_python.h and contrib/champ/champ_module.c
fixed in svn rev 4147