Created attachment 132084 [details]
Patch fixing the problem

Configure detects FC_GPERF_SIZE_T. When this type is size_t, the build fails because the prototypes in fcobjshash.h do not match the functions in fcobjs.c:

In file included from fcobjs.c:33:0:
fcobjshash.gperf:28:1: error: conflicting types for 'FcObjectTypeHash'
 "aspect",FC_ASPECT_OBJECT
 ^
fcobjs.c:28:1: note: previous declaration of 'FcObjectTypeHash' was here
 FcObjectTypeHash (register const char *str, register FC_GPERF_SIZE_T len);
 ^
In file included from fcobjs.c:33:0:
fcobjshash.gperf:172:1: error: conflicting types for 'FcObjectTypeLookup'
fcobjs.c:31:1: note: previous declaration of 'FcObjectTypeLookup' was here
 FcObjectTypeLookup (register const char *str, register FC_GPERF_SIZE_T len);

The attached patch fixes the build for me; I think the file is generated though, so you probably need to fix this differently.