Obtained 25 stack frames.
/usr/games/crawl-0.12(_Z17write_stack_traceP8_IO_FILEi+0x23) [0x5dc7d3]: write_stack_trace(_IO_FILE*, int)
/usr/games/crawl-0.12() [0x5dcb44]
/lib/x86_64-linux-gnu/libc.so.6(+0x324f0) [0x7f011cc654f0]: 
/lib/x86_64-linux-gnu/libpthread.so.0(raise+0x2b) [0x7f011cfcbefb]: 
/usr/games/crawl-0.12() [0x5e2684]
/usr/games/crawl-0.12(_Z12AssertFailedPKcS0_i+0x57) [0x5e27c7]: AssertFailed(char const*, char const*, int)
/usr/games/crawl-0.12() [0x5c585e]
/usr/games/crawl-0.12(_Z11real_colourjRK9coord_def+0x22) [0x5c5a12]: real_colour(unsigned int, coord_def const&)
/usr/games/crawl-0.12(_Z14get_cell_glyphRK9coord_defbi+0x198) [0x920b28]: get_cell_glyph(coord_def const&, bool, int)
/usr/games/crawl-0.12(_Z10screenshotv+0x16a) [0x9f49da]: screenshot()
/usr/games/crawl-0.12(_Z13do_crash_dumpv+0x1687) [0x5e4067]: do_crash_dump()
/usr/games/crawl-0.12() [0x5dca44]
/lib/x86_64-linux-gnu/libc.so.6(+0x324f0) [0x7f011cc654f0]: 
/lib/x86_64-linux-gnu/libc.so.6(__write+0x10) [0x7f011cd01af0]: 
/lib/x86_64-linux-gnu/libc.so.6(_IO_file_write+0x43) [0x7f011cca5e53]: 
/lib/x86_64-linux-gnu/libc.so.6(+0x72aca) [0x7f011cca5aca]: 
/lib/x86_64-linux-gnu/libc.so.6(_IO_file_xsputn+0x1fe) [0x7f011cca5dbe]: 
/lib/x86_64-linux-gnu/libc.so.6(fputs+0x9c) [0x7f011cc9ba0c]: 
/usr/games/crawl-0.12(_Z3endibPKcz+0x2db) [0x9a63cb]: end(int, bool, char const*, ...)
/usr/games/crawl-0.12(_Z9save_gamebPKc+0x142) [0x67e422]: save_game(bool, char const*)
/usr/games/crawl-0.12() [0x78c62d]
/usr/games/crawl-0.12() [0x78d0b5]
/usr/games/crawl-0.12(main+0x2e1) [0x4f1e41]: 
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7f011cc51ead]: 
/usr/games/crawl-0.12() [0x559191]