contrib: update nettle to 3.7.3

contrib/src/nettle/SHA512SUMS

-26aefbbe9927e90e28f271e56d2ba876611831222d0e1e1a58bdb75bbd50934fcd84418a4fe47b845f557e60a9786a72a4de2676c930447b104f2256aca7a54f  nettle-3.4.1.tar.gz
+9901eba305421adff6d551ac7f478dff3f68a339d444c776724ab0b977fe6be792b1d2950c8705acbe76bd924fd6d898a65eded546777884be3b436d0e052437  nettle-3.7.3.tar.gz

contrib/src/nettle/fix-cc-for-build.patch

-From 91df68136ad1562cf9217599254706d8cfa970ea Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Adrien=20B=C3=A9raud?= <adrien.beraud@savoirfairelinux.com>
-Date: Sun, 20 Sep 2020 19:35:54 +0200
-Subject: [PATCH] m4: follow GMP changes for GMP_PROG_CC_FOR_BUILD
-
----
- aclocal.m4 | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/aclocal.m4 b/aclocal.m4
-index 513b2df4..e81e0351 100644
---- a/aclocal.m4
-+++ b/aclocal.m4
-@@ -369,7 +369,7 @@ cat >conftest.c <<EOF
- int
- main ()
- {
--  exit(0);
-+  return 0;
- }
- EOF
- gmp_compile="$1 conftest.c"
-@@ -410,7 +410,7 @@ else
- int
- main ()
- {
--  exit (0);
-+  return 0;
- }
- EOF
-   for i in .exe ,ff8 ""; do
--- 
-GitLab
-

contrib/src/nettle/rules.mak

 # Nettle
 
-NETTLE_VERSION := 3.4.1
+NETTLE_VERSION := 3.7.3
 NETTLE_URL := $(GNU)/nettle/nettle-$(NETTLE_VERSION).tar.gz
 
 ifeq ($(call need_pkg,"nettle >= 3.4.1"),)
@@ -21,7 +21,6 @@ $(TARBALLS)/nettle-$(NETTLE_VERSION).tar.gz:
 
 nettle: nettle-$(NETTLE_VERSION).tar.gz .sum-nettle
 	$(UNPACK)
-	$(APPLY) $(SRC)/nettle/fix-cc-for-build.patch
 	$(MOVE)
 
 DEPS_nettle = gmp $(DEPS_gmp)