Use CURL_LIBRARIES (plural) instead of CURL_LIBRARY (singular).

Modern CMake's FindCURL.cmake (since 3.4) sets CURL_LIBRARIES, not the
deprecated singular CURL_LIBRARY. SWORD 1.9.0 references the singular
form, which silently expands to nothing — leaving libsword.so with
unresolved curl_easy_* symbols and breaking any downstream binary that
links against it.

Worth reporting upstream to crosswire.org.

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -216,7 +216,7 @@ IF(WITH_CURL)
 		ENDIF(CURL_CONFIG_OUTPUT STREQUAL "1")
 	ENDIF(CURL_CONFIG)
 	INCLUDE_DIRECTORIES(${CURL_INCLUDE_DIRS})
-	SET(SWORD_LINK_LIBRARIES ${SWORD_LINK_LIBRARIES} ${CURL_LIBRARY})
+	SET(SWORD_LINK_LIBRARIES ${SWORD_LINK_LIBRARIES} ${CURL_LIBRARIES})
 ENDIF(WITH_CURL)

 IF(WITH_CLUCENE)