correct issue to build on buster

.gitlab-ci.yml

@@ -1285,6 +1285,7 @@ Linux client debian_amd64_buster build:
                          libfreetype6-dev
                          libgif-dev
                          libgl1-mesa-dev
+                         libgnutls28-dev
                          libjpeg62-turbo-dev
                          liblzma-dev
                          libopenal-dev
@@ -1353,6 +1354,7 @@ Linux client_appimage debian_amd64_buster build:
                          libfreetype6-dev
                          libgif-dev
                          libgl1-mesa-dev
+                         libgnutls28-dev
                          libjpeg62-turbo-dev
                          liblzma-dev
                          libopenal-dev

code/CMakeModules/Findgnutls.cmake

@@ -4,6 +4,17 @@
 #  GNUTLS_FOUND, if false, do not try to link to JPEG
 #  GNUTLS_INCLUDE_DIR, where to find headers.
 
+IF(NOT UNIX)
+   MESSAGE(STATUS "Ignore gnutls: It's not Unix enviroment")
+   RETURN()
+ENDIF()
+
+GET_CMAKE_PROPERTY(_variableNames VARIABLES)
+LIST (SORT _variableNames)
+FOREACH (_variableName ${_variableNames})
+    MESSAGE(STATUS "${_variableName}=${${_variableName}}")
+ENDFOREACH()
+
 IF(GNUTLS_LIBRARY AND GNUTLS_INCLUDE_DIR)
   # in cache already
   SET(GNUTLS_FIND_QUIETLY TRUE)