Make symbols hidden

CMakeLists.txt

@@ -5,6 +5,8 @@ project(libXISF VERSION 0.2.0 LANGUAGES CXX C)
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+set(CMAKE_CXX_VISIBILITY_PRESET hidden)
 
 option(BUILD_SHARED_LIBS "Build using shared libraries" ON)
 
@@ -21,15 +23,25 @@ add_library(XISF
   lz4/lz4hc.c
   lz4/lz4hc.h
   pugixml/pugixml.cpp
+  zlib/adler32.c
+  zlib/compress.c
+  zlib/crc32.c
+  zlib/deflate.c
+  zlib/gzclose.c
+  zlib/gzlib.c
+  zlib/gzread.c
+  zlib/gzwrite.c
+  zlib/inflate.c
+  zlib/infback.c
+  zlib/inftrees.c
+  zlib/inffast.c
+  zlib/trees.c
+  zlib/uncompr.c
+  zlib/zutil.c
 )
 
-add_subdirectory(zlib)
-set_target_properties(zlibstatic PROPERTIES POSITION_INDEPENDENT_CODE ${BUILD_SHARED_LIBS})
-
 set_target_properties(XISF PROPERTIES VERSION ${PROJECT_VERSION} SOVERSION ${PROJECT_VERSION_MAJOR})
 
-target_link_libraries(XISF PUBLIC zlibstatic)
-
 if(BUILD_SHARED_LIBS)
     target_compile_definitions(XISF PRIVATE LIBXISF_LIBRARY)
 else(BUILD_SHARED_LIBS)