Fix libzip version check

externals/find-modules/FindLibzip.cmake

@@ -28,26 +28,27 @@ find_library(LIBZIP_LIBRARY
   "$ENV{LIB_DIR}/lib" "$ENV{LIB}" /usr/local/lib /usr/lib
 )
 
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(Libzip
-  FOUND_VAR LIBZIP_FOUND
-  REQUIRED_VARS
-    LIBZIP_LIBRARY
-    LIBZIP_INCLUDE_DIR
-    LIBZIP_INCLUDE_DIR_ZIPCONF
-)
-
-set(LIBZIP_VERSION 0)
-
 if (LIBZIP_INCLUDE_DIR_ZIPCONF)
   FILE(READ "${LIBZIP_INCLUDE_DIR_ZIPCONF}/zipconf.h" _LIBZIP_VERSION_CONTENTS)
   if (_LIBZIP_VERSION_CONTENTS)
     STRING(REGEX REPLACE ".*#define LIBZIP_VERSION \"([0-9.]+)\".*" "\\1" LIBZIP_VERSION "${_LIBZIP_VERSION_CONTENTS}")
   endif()
+  unset(_LIBZIP_VERSION_CONTENTS)
 endif()
 
 set(LIBZIP_VERSION ${LIBZIP_VERSION} CACHE STRING "Version number of libzip")
 
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Libzip
+  FOUND_VAR LIBZIP_FOUND
+  REQUIRED_VARS
+    LIBZIP_LIBRARY
+    LIBZIP_INCLUDE_DIR
+    LIBZIP_INCLUDE_DIR_ZIPCONF
+    LIBZIP_VERSION
+  VERSION_VAR LIBZIP_VERSION
+)
+
 if(LIBZIP_FOUND)
   set(LIBZIP_LIBRARIES ${LIBZIP_LIBRARY})
   set(LIBZIP_INCLUDE_DIRS ${LIBZIP_INCLUDE_DIR})
@@ -65,5 +66,7 @@ endif()
 
 mark_as_advanced(
     LIBZIP_INCLUDE_DIR
+    LIBZIP_INCLUDE_DIR_ZIPCONF
     LIBZIP_LIBRARY
+    LIBZIP_VERSION
 )