diff -up gnupg-2.1.12/configure.ac.build gnupg-2.1.12/configure.ac
--- gnupg-2.1.12/configure.ac.build	2016-05-04 11:43:16.000000000 +0200
+++ gnupg-2.1.12/configure.ac	2016-05-05 12:05:07.314698224 +0200
@@ -90,8 +90,8 @@ 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
@@ -1636,7 +1636,7 @@ AC_ARG_ENABLE(optimization,
 #
 # Add user CFLAGS.
 #
-CFLAGS="$CFLAGS $CFLAGS_orig"
+# CFLAGS="$CFLAGS $CFLAGS_orig"
 
 #
 # Decide what to build
diff -up gnupg-2.1.12/configure.build gnupg-2.1.12/configure
--- gnupg-2.1.12/configure.build	2016-05-04 16:00:22.000000000 +0200
+++ gnupg-2.1.12/configure	2016-05-05 12:05:07.316698269 +0200
@@ -5043,8 +5043,8 @@ $as_echo "$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
@@ -15413,7 +15413,7 @@ fi
 #
 # Add user CFLAGS.
 #
-CFLAGS="$CFLAGS $CFLAGS_orig"
+# CFLAGS="$CFLAGS $CFLAGS_orig"
 
 #
 # Decide what to build
diff -up gnupg-2.1.12/dirmngr/Makefile.am.build gnupg-2.1.12/dirmngr/Makefile.am
--- gnupg-2.1.12/dirmngr/Makefile.am.build	2016-05-04 11:43:16.000000000 +0200
+++ gnupg-2.1.12/dirmngr/Makefile.am	2016-05-05 12:20:24.468656960 +0200
@@ -132,7 +132,7 @@ endif
 t_http_SOURCES = t-http.c http.c dns-stuff.c
 t_http_CFLAGS  = -DWITHOUT_NPTH=1 \
 	         $(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)
 
@@ -140,7 +140,7 @@ 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 \
+t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1 $(LIBASSUAN_CFLAGS) \
 			  $(LIBGCRYPT_CFLAGS) $(GPG_ERROR_CFLAGS)
 t_ldap_parse_uri_LDADD = $(ldaplibs) $(t_common_ldadd) $(DNSLIBS)
 
diff -up gnupg-2.1.12/dirmngr/Makefile.in.build gnupg-2.1.12/dirmngr/Makefile.in
--- gnupg-2.1.12/dirmngr/Makefile.in.build	2016-05-04 16:00:20.000000000 +0200
+++ gnupg-2.1.12/dirmngr/Makefile.in	2016-05-05 12:22:43.333832474 +0200
@@ -641,7 +641,7 @@ module_tests = t-dns-stuff $(am__append_
 t_http_SOURCES = t-http.c http.c dns-stuff.c
 t_http_CFLAGS = -DWITHOUT_NPTH=1 \
 	         $(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)
@@ -651,7 +651,7 @@ t_ldap_parse_uri_SOURCES = \
         http.c dns-stuff.c \
         $(ldap_url) $(t_common_src)
 
-t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1 \
+t_ldap_parse_uri_CFLAGS = -DWITHOUT_NPTH=1 $(LIBASSUAN_CFLAGS) \
 			  $(LIBGCRYPT_CFLAGS) $(GPG_ERROR_CFLAGS)
 
 t_ldap_parse_uri_LDADD = $(ldaplibs) $(t_common_ldadd) $(DNSLIBS)