Add annotations to create gnss-base.h

This is required to make sure that the constants in gps.h does not
ever go out of sync with the enums created out of them in the HAL
interface definition.

Test: mm

Change-Id: I103cf46d198e9f5de9e0cfd64f2795f0094ecb39
diff --git a/gnss/1.0/IGnss.hal b/gnss/1.0/IGnss.hal
index 24a5371..5cde79e 100644
--- a/gnss/1.0/IGnss.hal
+++ b/gnss/1.0/IGnss.hal
@@ -28,9 +28,10 @@
 import IGnssNi;
 import IGnssXtra;
 
-/* Represents the standard GNSS interface. */
+/* Represents the standard GNSS (Global Navigation Satellite System) interface. */
 interface IGnss {
     /* Requested operational mode for GNSS operation. */
+    @export(name="", value_prefix="GPS_POSITION_MODE_")
     enum GnssPositionMode : uint8_t {
         /** Mode for running GNSS standalone (no assistance). */
         STANDALONE  = 0,
@@ -44,6 +45,7 @@
     };
 
     /* Requested recurrence mode for GNSS operation. */
+    @export(name="", value_prefix="GPS_POSITION_")
     enum GnssPositionRecurrence : uint32_t {
         /** Receive GNSS fixes on a recurring basis at a specified period. */
         RECURRENCE_PERIODIC  = 0,
@@ -55,6 +57,7 @@
      * Flags used to specify which aiding data to delete when calling
      * deleteAidingData().
      */
+    @export(name="", value_prefix="GPS_")
     enum GnssAidingData : uint16_t {
         DELETE_EPHEMERIS    = 0x0001,
         DELETE_ALMANAC      = 0x0002,