This happens when compiling today's HEAD:

pkgio.c:1103: warning: passing argument 1 of 'headerLoad' discards qualifiers 
from pointer target type
pkgio.c:1105: error: 'RPMRC_BAD' undeclared (first use in this function)
pkgio.c:1105: error: (Each undeclared identifier is reported only once
pkgio.c:1105: error: for each function it appears in.)

The attached patch fixes the error (not the warning, but that one is probably 
harmless).