c-bindings: Add jsonnet_realloc export

This adds the realloc function as an export in c-bindings.go so
that it is included in the generated header and can be used by
dependent libraries.

c-bindings/c-bindings.go

@@ -663,5 +663,11 @@ func jsonnet_set_trace_out_callback(vmRef *C.struct_JsonnetVm, cb *C.JsonnetIoWr
 	vm.SetTraceOut(&traceOut{cb})
 }
 
+//export jsonnet_realloc
+func jsonnet_realloc(vmRef *C.struct_JsonnetVm, buf *C.char, sz C.size_t) *C.char {
+	return C.jsonnet_internal_realloc(vmRef, buf, sz)
+}
+
+
 func main() {
 }

c-bindings/internal.h

@@ -46,3 +46,5 @@ int jsonnet_internal_execute_writer(JsonnetIoWriterCallback *cb,
                                     int *success);
 
 void jsonnet_internal_free_string(char *str);
+
+char* jsonnet_internal_realloc(struct JsonnetVm *vm, char *str, size_t sz);

c-bindings/libjsonnet.cpp

@@ -72,7 +72,7 @@ static void memory_panic(void)
     abort();
 }
 
-char *jsonnet_realloc(JsonnetVm *vm, char *str, size_t sz)
+char *jsonnet_internal_realloc(JsonnetVm *vm, char *str, size_t sz)
 {
     (void)vm;
     if (str == nullptr) {