land: gps: fix build for OSS builds

Squash of the following commits:

gps: Correct forward declaration in proprietary definitions

The qcom prebuilt binary relies on FlpExtLocation_s,
so we cannot change it to FlpExtLocation.
This patch fixes it.

karate: gps: fix remove trailing space

In setXtraUserAgent,
size_t is unsigned and never being negative.
Will cause segmentation fault, if string is all space.

Change-Id: I1cf1f956943b0739640afe909954ade6921e28a1

gps/core/UlpProxyBase.h

@@ -30,7 +30,10 @@
 #define ULP_PROXY_BASE_H
 
 #include <gps_extended.h>
-#include "fused_location_extended.h"
+
+struct FlpExtLocation_s;
+struct FlpExtBatchOptions;
+
 namespace loc_core {
 
 class LocAdapterBase;
@@ -101,7 +104,7 @@ public:
         (void)active;
         return false;
     }
-    inline virtual bool reportPositions(const FlpExtLocation* locations,
+    inline virtual bool reportPositions(const struct FlpExtLocation_s* locations,
                                         int32_t number_of_locations) {
         (void)locations;
         (void)number_of_locations;

gps/loc_api/libloc_api_50001/LocEngAdapter.cpp

@@ -195,9 +195,11 @@ void LocEngAdapter::setXtraUserAgent() {
                 fclose(file);
 
                 // remove trailing spaces
-                size_t len = strlen(buf);
-                while (--len >= 0 && isspace(buf[len])) {
-                    buf[len] = '\0';
+                char *s;
+                s = buf + strlen(buf);
+                while (--s >= buf) {
+                    if (!isspace(*s)) break;
+                    *s = 0;
                 }
             }