This follows from http://thread.gmane.org/gmane.games.flightgear.devel/78650 and
resolves the sign bug https://sourceforge.net/p/flightgear/codetickets/1778/ .
Combined with a matching change to the flightgear repository, this changes the
HUD formats from the current set of 3 (note that the text in brackets is not
shown in the HUD preferences PUI dialog, but is show here for reference):
0) Decimal degrees (37.618890N -122.375000W)
1) Degrees, minutes (37*37.133N -122*22.500W)
2) Degrees, minutes, seconds (37*37 08.0 N -122*22 30.0 W)
to (here the text in brackets is shown in the PUI dialog):
0) DDD format (37.618890N 122.375000W)
1) DMM format (37*37.133'N 122*22.500'W)
2) DMS format (37*37'08.0"N 122*22'30.0"W)
3) Signed DDD format (37.618890 -122.375000)
4) Signed DMM format (37*37.133' -122*22.500')
5) Signed DMS format (37*37'08.0" -122*22'30.0")
6) Zero padded DDD (51.477500N 000.461389W)
7) Zero padded DMM (51*28.650'N 000*27.683'W)
8) Zero padded DMS (51*28'39.0"N 000*27'41.0"W)
9) Trinity House Navigation (51* 28'.650N 000* 27'.683W)
