gnu: nss: Fix build failure on armhf-linux.

Fixes <https://bugs.gnu.org/36930>.

* gnu/packages/patches/nss-freebl-stubs.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/nss.scm (nss)[source](patches): Add it.

gnu/local.mk

@@ -1119,6 +1119,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/nfs-utils-missing-headers.patch		\
   %D%/packages/patches/ngircd-handle-zombies.patch		\
   %D%/packages/patches/nm-plugin-path.patch			\
+  %D%/packages/patches/nss-freebl-stubs.patch			\
   %D%/packages/patches/nss-increase-test-timeout.patch		\
   %D%/packages/patches/nss-pkgconfig.patch			\
   %D%/packages/patches/ntfs-3g-CVE-2019-9755.patch		\

gnu/packages/nss.scm

@@ -84,6 +84,7 @@ in the Mozilla clients.")
                 "12sfq9xvpwpc22qnjsg1if1lmchiy33byrh92wn91phz7li0abqi"))
               ;; Create nss.pc and nss-config.
               (patches (search-patches "nss-pkgconfig.patch"
+                                       "nss-freebl-stubs.patch"
                                        "nss-increase-test-timeout.patch"))))
     (build-system gnu-build-system)
     (outputs '("out" "bin"))

gnu/packages/patches/nss-freebl-stubs.patch

@@ -0,0 +1,20 @@
+This patch is required for Makefile-based builds of NSS 3.45 on armhf-linux.
+
+Taken from upstream bug tracker:
+https://bugzilla.mozilla.org/show_bug.cgi?id=1571316
+
+diff --git a/nss/lib/freebl/ecl/curve25519_32.c b/nss/lib/freebl/ecl/curve25519_32.c
+--- a/nss/lib/freebl/ecl/curve25519_32.c
++++ b/nss/lib/freebl/ecl/curve25519_32.c
+@@ -29,6 +29,10 @@
+  *  1. Convert custom integer types to stdint.h types
+  */
+ 
++#ifdef FREEBL_NO_DEPEND
++#include "../stubs.h"
++#endif
++
+ #include "ecl-priv.h"
+ 
+ /* fe means field element. Here the field is \Z/(2^255-19). An element t,
+