libc gettext is never sufficient on musl

--- tigervnc-1.8.0/CMakeLists.txt.old	2017-05-16 08:53:28.000000000 -0500
+++ tigervnc-1.8.0/CMakeLists.txt	2017-09-10 16:05:13.397275098 -0500
@@ -152,9 +152,9 @@
       set(CMAKE_REQUIRED_LIBRARIES ${ICONV_LIBRARIES})
       set(CMAKE_REQUIRED_FLAGS -fno-builtin-dgettext)
       check_function_exists(dgettext LIBC_HAS_DGETTEXT)
-      if(LIBC_HAS_DGETTEXT)
-        set(GETTEXT_FOUND TRUE)
-      else()
+      #if(LIBC_HAS_DGETTEXT)
+      #  set(GETTEXT_FOUND TRUE)
+      #else()
         find_library(LIBINTL_LIBRARY NAMES intl libintl)
         if(LIBINTL_LIBRARY)
           check_library_exists(${LIBINTL_LIBRARY} "dgettext" "" LIBINTL_HAS_DGETTEXT)
@@ -163,7 +163,7 @@
             set(GETTEXT_FOUND TRUE)
           endif()
         endif()
-      endif()
+      #endif()
       set(CMAKE_REQUIRED_LIBRARIES)
       set(CMAKE_REQUIRED_FLAGS)
     endif()