Related: tdf#145127 force error when compiling for unsupported Apple OSs

While LibreOfficeKit can be built on macOS, the built library won't work
as intended since a headless vcl implementation is needed. Currently,
iOS is the only Apple OS that has a headless vcl implementation so
force a compiler error.

Change-Id: Ib9318851ff7e6c98531672ba7241c22a91f3ef7c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/180093
Reviewed-by: Patrick Luby <guibomacdev@gmail.com>
Tested-by: Jenkins

include/LibreOfficeKit/LibreOfficeKit.h

@@ -21,6 +21,10 @@
 # include <stdint.h>
 #endif
 
+#ifdef __APPLE__
+#include <TargetConditionals.h>
+#endif
+
 #include "LibreOfficeKitTypes.h"
 
 #ifdef __cplusplus

include/LibreOfficeKit/LibreOfficeKitInit.h

@@ -34,6 +34,14 @@
     #ifdef __APPLE__
         #define TARGET_LIB        "lib" "sofficeapp" ".dylib"
         #define TARGET_MERGED_LIB "lib" "mergedlo" ".dylib"
+
+        #if !defined TARGET_OS_IPHONE || TARGET_OS_IPHONE == 0
+            #if defined TARGET_OS_OSX && TARGET_OS_OSX == 1
+                #error LibreOfficeKit is not supported on macOS
+            #else
+                #error LibreOfficeKit is not supported on tvOS, visionOS or watchOS
+            #endif
+        #endif
     #else
         #define TARGET_LIB        "lib" "sofficeapp" ".so"
         #define TARGET_MERGED_LIB "lib" "mergedlo" ".so"