As an FYI, I get these at compile time:
Don't know if they mean anything, but thought I'd mention them.

gcc -I. -I.ext/include/i386-mingw32 -I./include -I.
-DONIG_ENC_REGISTER=rb_enc_register  -O0 -g3 -ggdb -Wall
-Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings
-Wno-long-long  -o enc/trans/gb18030.o -c ./enc/trans/gb18030.c
C:/DOCUME~1/packrd/LOCALS~1/Temp/ccga14cs.s: Assembler messages:
C:/DOCUME~1/packrd/LOCALS~1/Temp/ccga14cs.s:154137: Warning: .stabs:
description field '174af' too big, try a different debug format
C:/DOCUME~1/packrd/LOCALS~1/Temp/ccga14cs.s:154138: Warning: .stabs:
description field '174ae' too big, try a different debug format
C:/DOCUME~1/packrd/LOCALS~1/Temp/ccga14cs.s:154139: Warning: .stabs:
description field '174ae' too big, try a different debug format
C:/DOCUME~1/packrd/LOCALS~1/Temp/ccga14cs.s:154140: Warning: .stabs:
description field '174ae' too big, try a different debug format
...

Thanks.
-r