Use -fvisibility=hidden to hide symbols by default;

This saves some space, and it's better to be conscious about symbol exports.

CMakeLists.txt

@@ -1,4 +1,5 @@
 cmake_minimum_required(VERSION 3.1.0)
+cmake_policy(SET CMP0063 NEW)
 project(lovr)
 
 # Options
@@ -319,6 +320,7 @@ else()
   add_executable(lovr ${LOVR_SRC})
 endif()
 
+set_target_properties(lovr PROPERTIES C_VISIBILITY_PRESET default)
 set_target_properties(lovr PROPERTIES C_STANDARD 99)
 target_include_directories(lovr PRIVATE src)
 target_link_libraries(lovr

src/headset/oculus_mobile_bridge.h

@@ -1,6 +1,7 @@
 // Functions on the Lovr side of the wall, called from the Oculus side of the wall.
 #pragma once
 
+#include "../util.h"
 #include <stdbool.h>
 
 // What's going on here:
@@ -81,18 +82,17 @@ typedef struct {
   BridgeLovrDevice deviceType;
 } BridgeLovrInitData;
 
-void bridgeLovrInit(BridgeLovrInitData *initData);
+LOVR_EXPORT void bridgeLovrInit(BridgeLovrInitData *initData);
 
-void bridgeLovrUpdate(BridgeLovrUpdateData *updateData);
+LOVR_EXPORT void bridgeLovrUpdate(BridgeLovrUpdateData *updateData);
 
 typedef struct {
   int eye;
   int framebuffer;
 } BridgeLovrDrawData;
 
-void bridgeLovrDraw(BridgeLovrDrawData *drawData);
+LOVR_EXPORT void bridgeLovrDraw(BridgeLovrDrawData *drawData);
 
-void bridgeLovrPaused(bool paused);
-
-void bridgeLovrClose();
+LOVR_EXPORT void bridgeLovrPaused(bool paused);
 
+LOVR_EXPORT void bridgeLovrClose();

src/util.h

@@ -6,7 +6,7 @@
 #ifdef _WIN32
 #define LOVR_EXPORT __declspec(dllexport)
 #else
-#define LOVR_EXPORT
+#define LOVR_EXPORT __attribute__((visibility("default")))
 #endif
 
 #ifndef _Noreturn