gnutls: fix certificate loading on Darwin

Certificate loading failed when gnutls build with clang 12.
A possible workaround is to build libtasn1 with optimization O1
Also, this patch fixes the libtasn1 build compiled with O1.

Gitlab: #493
Change-Id: I698d8212801e2cc65661e64e7f5fee3eacbc7c5a

contrib/src/gnutls/0001-use-system-isdigit.patch

+From 2da87398f460ba2e671456dd5a88568b751d86bc Mon Sep 17 00:00:00 2001
+From: kkostiuk <kateryna.kostiuk@savoirfairelinux.com>
+Date: Sun, 28 Mar 2021 14:42:30 -0400
+Subject: [PATCH] use system isdigit
+
+---
+ lib/minitasn1/parser_aux.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/lib/minitasn1/parser_aux.c b/lib/minitasn1/parser_aux.c
+index d5dbbf8..ac1db6f 100644
+--- a/lib/minitasn1/parser_aux.c
++++ b/lib/minitasn1/parser_aux.c
+@@ -26,7 +26,9 @@
+ #include "gstr.h"
+ #include "structure.h"
+ #include "element.h"
+-#include "c-ctype.h"
++#include "ctype.h"
++#undef c_isdigit
++#define c_isdigit isdigit
+ 
+ char _asn1_identifierMissing[ASN1_MAX_NAME_SIZE + 1];	/* identifier name not found */
+ 
+-- 
+2.24.3 (Apple Git-128)
+

contrib/src/gnutls/rules.mak

@@ -25,6 +25,9 @@ endif
 ifdef HAVE_ANDROID
 	$(APPLY) $(SRC)/gnutls/no-create-time-h.patch
 endif
+ifdef HAVE_DARWIN_OS
+	$(APPLY) $(SRC)/gnutls/0001-use-system-isdigit.patch
+endif
 ifdef HAVE_MACOSX
 	$(APPLY) $(SRC)/gnutls/gnutls-disable-getentropy-osx.patch
 endif
@@ -70,11 +73,13 @@ endif
 ifdef HAVE_ANDROID
 	cd $< && $(HOSTVARS) gl_cv_header_working_stdint_h=yes ./configure $(GNUTLS_CONF)
 else
+#use O1 to compile gnutls on darwin platforms. It is a workaround to fix
+#libtasn1 certificate loading https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252548
 ifdef HAVE_IOS
-	cd $< && $(HOSTVARS) ac_cv_func_clock_gettime=no CFLAGS="$(CFLAGS)" ./configure $(GNUTLS_CONF)
+	cd $< && $(HOSTVARS) ac_cv_func_clock_gettime=no CFLAGS="$(CFLAGS) -O1" ./configure $(GNUTLS_CONF)
 else
 ifdef HAVE_MACOSX
-	cd $< && $(HOSTVARS) ac_cv_func_clock_gettime=no CFLAGS="$(CFLAGS)" ./configure $(GNUTLS_CONF)
+	cd $< && $(HOSTVARS) ac_cv_func_clock_gettime=no CFLAGS="$(CFLAGS) -O1" ./configure $(GNUTLS_CONF)
 else
 	cd $< && $(HOSTVARS) CFLAGS="$(CFLAGS)" ./configure $(GNUTLS_CONF)
 endif