Set default visibility to hidden

CMakeLists.txt

@@ -14,6 +14,8 @@ add_compile_options(-Wall -Wextra -Wformat
   -Werror
 )
 
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED TRUE)
 set(CMAKE_C_EXTENSIONS FALSE)

include/ovni.h.in

@@ -4,6 +4,8 @@
 #ifndef OVNI_H
 #define OVNI_H
 
+#pragma GCC visibility push(default)
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -171,4 +173,6 @@ void ovni_flush(void);
 }
 #endif
 
+#pragma GCC visibility pop
+
 #endif /* OVNI_H */