add uint64 data to json-c

CMakeLists.txt

@@ -142,6 +142,7 @@ endif()
 
 if (MSVC)
     check_symbol_exists(strtoll     "stdlib.h" HAVE_STRTOLL)
+    check_symbol_exists(strtoull    "stdlib.h" HAVE_STRTOULL)
 
     set(json_c_strtoll "strtoll")
     if (NOT HAVE_STRTOLL)
@@ -153,6 +154,16 @@ if (MSVC)
             # could do the same for strtoull, if needed
         endif()
     endif()
+
+    set(json_c_strtoull "strtoull")
+    if (NOT HAVE_STRTOULL)
+        # Use _strtoui64 if strtoull is not available.
+        check_symbol_exists(_strtoui64 "stdlib.h" __have_strtoui64)
+        if (__have_strtoui64)
+            set(HAVE_STRTOULL 1)
+            set(json_c_strtoull "_strtoui64")
+        endif()
+    endif()
 endif()