fix(libacron/acronc): complete cross-platform build

This patch made several changes to correctly build libac on Windows:

1. Deprecated PkgConfig on Unix. On both platforms, libac requires the JSON-C CMake module to locate libraries (whether is dynamic or static) and headers. On Windows, the common practice is to statically link the library, so libac now provides setup.bat to automatically clone JSON-C and build it. In CMakeLists.txt, libac will automatically pick up the in-tree JSON-C build if it presents. Otherwise, it will use the system default's. Users can override the CMAKE_PREFIX_PATH to supply a custom JSON-C library if it is not found in-tree.
2. Switched from #include <json-c/xxx.h> to <xxx.h>, as the former (current) approach is non-standard and depends on the system header locations. The later (new) approach relies on CMake to supply header search paths, which works on Windows as well.
3. Deprecated --version-script on Unix linkers. Instead, libac now uses -fvisibility (https://gcc.gnu.org/wiki/Visibility) on GCC or LLVM, as well as __declspec(dllexport) on MSVC to export selected symbols. A new macro, LIBAC_EXPORT, is defined in incl.h (new), and all functions needed to export are marked with that macro.
4. Changed several codes (mostly socket-related) to work on Windows.
5. Massive rewrite of CMake in preparation of further installation and static library support.

Signed-off-by: Trumeet <yuuta@yuuta.moe>

1 files changed, 4 insertions, 3 deletions

diff --git a/client/libacron/include/net.h b/client/libacron/include/net.h
index 8fb33f8..6d8d9e7 100644
--- a/client/libacron/include/net.h
+++ b/client/libacron/include/net.h
@@ -5,6 +5,7 @@
 #ifndef LIBAC_NET_H
 #define LIBAC_NET_H
 
+#include "incl.h"
 #include "common.h"
 #include "events.h"
 #include "requests.h"
@@ -27,7 +28,7 @@ typedef struct ac_connection_parameters {
  * @return AC_E_OK or an error code. When failed, *out will be untouched.
  * MT-Safe
  */
-int ac_connect(ac_connection_parameters_t parameters, void **out);
+LIBAC_EXPORT int ac_connect(ac_connection_parameters_t parameters, void **out);
 
 /**
  * Disconnect the connection.
@@ -35,7 +36,7 @@ int ac_connect(ac_connection_parameters_t parameters, void **out);
  * @return AC_E_OK or an error code. When failed, connection is undefined. When succeeds, connection is freed and invalid.
  * MT-Unsafe
  */
-int ac_disconnect(void *connection);
+LIBAC_EXPORT int ac_disconnect(void *connection);
 
 /**
  * Blocks the current thread until a new response or event arrives.
@@ -43,6 +44,6 @@ int ac_disconnect(void *connection);
  * @param response Output response of either an event or a response. May be NULL even if it succeeds.
  * @return AC_E_OK or an error code. When failed, *response is NULL.
  */
-int ac_receive(void *connection, ac_obj_t **response);
+LIBAC_EXPORT int ac_receive(void *connection, ac_obj_t **response);
 
 #endif /* LIBAC_NET_H */