Found the following significant warnings:
  redefine.c:147:40: warning: pointer targets in passing argument 2 of ‘strbuf_gets’ differ in signedness [-Wpointer-sign]
  redefine.c:147:10: warning: pointer targets in returning ‘unsigned char *’ from a function with return type ‘char *’ differ in signedness [-Wpointer-sign]
  redefine.c:155:45: warning: pointer targets in passing argument 2 of ‘strbuf_vprintf’ differ in signedness [-Wpointer-sign]
  redefine.c:166:40: warning: pointer targets in passing argument 2 of ‘strbuf_puts’ differ in signedness [-Wpointer-sign]
  rulebasedmodels.c:205:12: warning: pointer targets in returning ‘unsigned char *’ from a function with return type ‘char *’ differ in signedness [-Wpointer-sign]
  strbuf.c:206:30: warning: pointer targets in passing argument 1 of ‘vsnprintf’ differ in signedness [-Wpointer-sign]
  strbuf.c:206:45: warning: pointer targets in passing argument 3 of ‘vsnprintf’ differ in signedness [-Wpointer-sign]
  strbuf.c:241:27: warning: pointer targets in passing argument 1 of ‘vsnprintf’ differ in signedness [-Wpointer-sign]
  strbuf.c:241:42: warning: pointer targets in passing argument 3 of ‘vsnprintf’ differ in signedness [-Wpointer-sign]
  strbuf.c:268:37: warning: pointer targets in passing argument 1 of ‘strlen’ differ in signedness [-Wpointer-sign]
  top.c:47:41: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
  top.c:53:41: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
  top.c:69:25: warning: pointer targets in initialization of ‘char *’ from ‘unsigned char *’ differ in signedness [-Wpointer-sign]
  top.c:109:41: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
  top.c:112:41: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
  top.c:115:41: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
  top.c:119:42: warning: pointer targets in passing argument 1 of ‘strbuf_create_full’ differ in signedness [-Wpointer-sign]
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/Cubist.Rcheck/00install.out’ for details.