Explicitly add gpg-error library in linker flags

component/gnutls/buildout.cfg

@@ -19,7 +19,7 @@ configure-options =
   --with-gpg-error-prefix=${gpg-error:location}
 environment =
   CPPFLAGS=-I${gpg-error:location}/include
-  LDFLAGS=-L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
+  LDFLAGS=-lgpg-error -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
 
 [gnutls]
 # XXX-Cedric : update to latest gnutls
@@ -30,5 +30,5 @@ configure-options =
   --with-libgcrypt-prefix=${gcrypt:location}
 environment =
   CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${ncurses:location}/include -I${ncurses:location}/include/ncursesw -I${gcrypt:location}/include -I${gpg-error:location}/include
-  LDFLAGS=-L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${gcrypt:location}/lib -Wl,-rpath=${gcrypt:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
+  LDFLAGS=-lgcrypt -L${readline:location}/lib -Wl,-rpath=${readline:location}/lib -L${ncurses:location}/lib -Wl,-rpath=${ncurses:location}/lib -L${gcrypt:location}/lib -Wl,-rpath=${gcrypt:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${gpg-error:location}/lib -Wl,-rpath=${gpg-error:location}/lib
   PKG_CONFIG=${zlib:location}/lib/pkgconfig