diff -up gnupg-2.1.17/configure.ac.build gnupg-2.1.17/configure.ac
--- gnupg-2.1.17/configure.ac.build	2016-12-20 11:19:05.000000000 +0100
+++ gnupg-2.1.17/configure.ac	2016-12-22 08:58:51.115299092 +0100
@@ -89,8 +89,8 @@ AC_GNU_SOURCE
 # CFLAGS (they are restored at the end of the configure script).  This
 # is because some configure checks don't work with -Werror, but we'd
 # like to use -Werror with our build.
-CFLAGS_orig=$CFLAGS
-CFLAGS=
+#CFLAGS_orig=$CFLAGS
+#CFLAGS=
 
 # Some status variables.
 have_gpg_error=no
@@ -1623,7 +1623,7 @@ AC_ARG_ENABLE(optimization,
 #
 # Add user CFLAGS.
 #
-CFLAGS="$CFLAGS $CFLAGS_orig"
+# CFLAGS="$CFLAGS $CFLAGS_orig"
 
 #
 # Decide what to build
diff -up gnupg-2.1.17/configure.build gnupg-2.1.17/configure
--- gnupg-2.1.17/configure.build	2016-12-20 11:28:20.000000000 +0100
+++ gnupg-2.1.17/configure	2016-12-22 08:58:51.116299114 +0100
@@ -5039,8 +5039,8 @@ $as_echo "$ac_cv_safe_to_define___extens
 # CFLAGS (they are restored at the end of the configure script).  This
 # is because some configure checks don't work with -Werror, but we'd
 # like to use -Werror with our build.
-CFLAGS_orig=$CFLAGS
-CFLAGS=
+#CFLAGS_orig=$CFLAGS
+#CFLAGS=
 
 # Some status variables.
 have_gpg_error=no
@@ -15465,7 +15465,7 @@ fi
 #
 # Add user CFLAGS.
 #
-CFLAGS="$CFLAGS $CFLAGS_orig"
+# CFLAGS="$CFLAGS $CFLAGS_orig"
 
 #
 # Decide what to build
diff -up gnupg-2.1.17/dirmngr/Makefile.am.build gnupg-2.1.17/dirmngr/Makefile.am
--- gnupg-2.1.17/dirmngr/Makefile.am.build	2016-12-22 08:58:51.116299114 +0100
+++ gnupg-2.1.17/dirmngr/Makefile.am	2016-12-22 09:01:02.632165482 +0100
@@ -141,7 +141,7 @@ endif
 t_http_SOURCES = $(t_common_src) t-http.c http.c dns-stuff.c
 t_http_CFLAGS  = -DWITHOUT_NPTH=1  $(USE_C99_CFLAGS) \
 	         $(LIBGCRYPT_CFLAGS) $(NTBTLS_CFLAGS) $(LIBGNUTLS_CFLAGS) \
-                 $(GPG_ERROR_CFLAGS)
+                 $(GPG_ERROR_CFLAGS) $(LIBASSUAN_CFLAGS)
 t_http_LDADD   = $(t_common_ldadd) \
 	         $(NTBTLS_LIBS) $(LIBGNUTLS_LIBS) $(DNSLIBS)
 
@@ -149,7 +149,7 @@ t_ldap_parse_uri_SOURCES = \
 	t-ldap-parse-uri.c ldap-parse-uri.c ldap-parse-uri.h \
         http.c dns-stuff.c \
         $(ldap_url) $(t_common_src)
-t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1  $(USE_C99_CFLAGS) \
+t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1 $(LIBASSUAN_CFLAGS) $(USE_C99_CFLAGS) \
 			  $(LIBGCRYPT_CFLAGS) $(GPG_ERROR_CFLAGS)
 t_ldap_parse_uri_LDADD = $(ldaplibs) $(t_common_ldadd) $(DNSLIBS)
 
diff -up gnupg-2.1.17/dirmngr/Makefile.in.build gnupg-2.1.17/dirmngr/Makefile.in
--- gnupg-2.1.17/dirmngr/Makefile.in.build	2016-12-22 08:58:51.117299136 +0100
+++ gnupg-2.1.17/dirmngr/Makefile.in	2016-12-22 09:02:03.802492934 +0100
@@ -665,7 +665,7 @@ module_tests = $(am__append_13)
 t_http_SOURCES = $(t_common_src) t-http.c http.c dns-stuff.c
 t_http_CFLAGS = -DWITHOUT_NPTH=1  $(USE_C99_CFLAGS) \
 	         $(LIBGCRYPT_CFLAGS) $(NTBTLS_CFLAGS) $(LIBGNUTLS_CFLAGS) \
-                 $(GPG_ERROR_CFLAGS)
+                 $(GPG_ERROR_CFLAGS) $(LIBASSUAN_CFLAGS)
 
 t_http_LDADD = $(t_common_ldadd) \
 	         $(NTBTLS_LIBS) $(LIBGNUTLS_LIBS) $(DNSLIBS)
@@ -675,7 +675,7 @@ t_ldap_parse_uri_SOURCES = \
         http.c dns-stuff.c \
         $(ldap_url) $(t_common_src)
 
-t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1  $(USE_C99_CFLAGS) \
+t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1 $(LIBASSUAN_CFLAGS) $(USE_C99_CFLAGS) \
 			  $(LIBGCRYPT_CFLAGS) $(GPG_ERROR_CFLAGS)
 
 t_ldap_parse_uri_LDADD = $(ldaplibs) $(t_common_ldadd) $(DNSLIBS)