Segmentation fault in genapts

Hello
I am trying to build 3 arcsecond scenery for the UK, and am getting a 
consistent segfault from genapts.  Here is a gdb listing:
[jonathan@localhost airports]$ gdb /usr/local/bin/genapts
GNU gdb 5.3-22mdk (Mandrake Linux)
(gdb) set args --input=runways.dat.gz --work=../../work --min-lon=-11 
--max-lon=+2 --min-lat=49 --max-lat=60
(gdb) run
...[# Builds 49 airports, then]...
Skipping airport EG13
Building EG13
e000n50/e000n52/2958266
This runway is not long enough for visual markings!

Program received signal SIGSEGV, Segmentation fault.
0x080efa55 in gpc_polygon_clip (op=GPC_DIFF, subj=0x859bdc0,
    clip=0x859bdc0, result=0x858d988) at gpc.c:1658
1658    gpc.c: No such file or directory.
        in gpc.c
Current language:  auto; currently c
(gdb) where
#0  0x080efa55 in gpc_polygon_clip (op=GPC_DIFF, subj=0x859bdc0,
    clip=0x859bdc0, result=0x858d988) at gpc.c:1658
#1  0x080b074a in polygon_clip(clip_op, TGPolygon const&, TGPolygon const&)
    (poly_op=POLY_DIFF, subject=@0xbfffd3b0, clip=@0xbfffe6e0)
    at polygon.cxx:381
#2  0x080b0a18 in polygon_diff(TGPolygon const&, TGPolygon const&) (
    subject=@0xbfffd3b0, clip=@0xbfffe6e0) at polygon.cxx:420
#3  0x0809e763 in gen_runway_section(TGRunway const&, TGPolygon const&, 
double, double, double, double, double, double, double, double, double, 
std::string const&, std::string const&, std::vector<TGSuperPoly, 
std::allocator<TGSuperPoly> >*, std::vector<TGTexParams, 
std::allocator<TGTexParams> >*, TGPolygon*) (rwy_info=@0x85565e0, 
runway=@0x833ff08,
    startl_pct=0.64084636556219443, endl_pct=0.82042468278109726,
    startw_pct=0, endw_pct=1, minu=0, maxu=1, minv=0, maxv=1, heading=270,
    prefix=@0xbfffda80, material=@0xbfffd710, rwy_polys=0xbfffe900,
    texparams=0xbfffe8f0, accum=0xbfffe6e0) at rwy_common.cxx:206
#4  0x080a9def in gen_visual_rwy(TGRunway const&, double, std::string const&, 
std::vector<TGSuperPoly, std::allocator<TGSuperPoly> >*, 
std::vector<TGTexParams, std::allocator<TGTexParams> >*, TGPolygon*) 
(rwy_info=@0x85565e0,
    alt_m=1712.9759521484375, material=@0xbfffda80, rwy_polys=0xbfffe900,
    texparams=0xbfffe8f0, accum=0xbfffe6e0)
    at /usr/include/c++/3.2.2/bits/stl_alloc.h:664
#5  0x08051681 in build_runway (rwy_info=@0x85565e0,

Here is the info for the offending airport:
[jonathan@localhost airports]$ zgrep -i EG13 runways.dat.gz
A EG13    50 CNY Burnham
R EG13 27   52.936573    0.666600 270.00  1837   164 NAVNN NNNN    0    0 NNNN    
0    0

I compiled gpc version 2.31 in the process of building TerraGear from the cvs 
sources yesterday.  The data was checked out of FlightGear cvs on 1-Apr.  I'm 
afraid that I don't understand the traceback information above - can anyone 
help?

Jonathan