Fix azimuth_long_path

* Return the correct long path azimuth (thanks P.J. Rovero, KK1D)
* Update configure.ac to use our fixed locator.c if hamlib <= 1.2.9

configure.ac

@@ -252,8 +252,8 @@ AC_FLDIGI_PKG_CHECK([hamlib], [hamlib >= 1.2.4], [yes], [yes],
                     [use hamradio control libraries @<:@autodetect@:>@],
                     [ENABLE_HAMLIB])
 # We compile our own copy of hamlib's locator.c if hamlib is not available
-# or if it is version <= 1.2.8, which has a broken qrb function
-AX_COMPARE_VERSION([$pkg_hamlib_version], [le], [1.2.8], [need_locator_c=yes], [need_locator_c=no])
+# or if it is version <= 1.2.9, which has a broken azimuth_long_path function
+AX_COMPARE_VERSION([$pkg_hamlib_version], [le], [1.2.9], [need_locator_c=yes], [need_locator_c=no])
 AM_CONDITIONAL([NEED_HAMLIB_LOCATOR], [test "$need_locator_c" = "yes"])
 
 ### libintl

src/misc/locator.c

@@ -587,7 +587,7 @@ double HAMLIB_API distance_long_path(double distance) {
  */
 
 double HAMLIB_API azimuth_long_path(double azimuth) {
-	return 360.0 - azimuth;
+	return azimuth + (azimuth <= 180.0 ? 180.0 : -180.0);
 }
 
 /*! @} */