diff --git a/SoObjects/Mailer/GNUmakefile.preamble b/SoObjects/Mailer/GNUmakefile.preamble
index de48776be..7ec8fa096 100644
--- a/SoObjects/Mailer/GNUmakefile.preamble
+++ b/SoObjects/Mailer/GNUmakefile.preamble
@@ -1,4 +1,18 @@
 # compilation settings
+ifeq ($(HAS_LIBRARY_gnutls),yes)
+ADDITIONAL_CPPFLAGS += -DHAVE_GNUTLS=1
+SOGo_LIBRARIES_DEPEND_UPON += -lgnutls
+else
+ifeq ($(HAS_LIBRARY_ssl),yes)
+ADDITIONAL_CPPFLAGS += -DHAVE_OPENSSL=1
+SOGo_LIBRARIES_DEPEND_UPON += -lcrypto
+endif
+endif
+
+ifeq ($(HAS_LIBRARY_ssl),yes)
+ADDITIONAL_CPPFLAGS += -DHAVE_OPENSSL=1
+BUNDLE_LIBS += -lcrypto
+endif
 
 ADDITIONAL_CPPFLAGS += \
         -Wall -DCOMPILE_FOR_GSTEP_MAKE=1        \