omGeneric.c, at line 618, performs

sprintf(rotate_font_ptr, "%s-%s", rotate_font_ptr, fields[field_num]);

This is not supposed to work: the standard prototype of sprintf is

int sprintf(char *restrict s, const char *restrict format, ...);

i.e. s is not supposed to appear in the arguments. It happens that I'm
getting a warning from valgrind:

==15975== Source and destination overlap in mempcpy(0x512D6D8, 0x512D6D8, 26)
==15975==    at 0x4026506: mempcpy (mc_replace_strmem.c:676)
==15975==    by 0x41E503D: _IO_default_xsputn (genops.c:469)
==15975==    by 0x41BE98A: vfprintf (vfprintf.c:1560)
==15975==    by 0x41D9FEB: vsprintf (iovsprintf.c:43)
==15975==    by 0x41C430D: sprintf (sprintf.c:34)
==15975==    by 0x55C02C8: get_rotate_fontname (omGeneric.c:618)

Can't we just call strcat?