diff --git a/Documentation/RelNotes/2.21.0.txt b/Documentation/RelNotes/2.21.0.txt
index 8a9a8dd496..7a49deddf3 100644
--- a/Documentation/RelNotes/2.21.0.txt
+++ b/Documentation/RelNotes/2.21.0.txt
@@ -26,7 +26,7 @@ UI, Workflows & Features
    the fast-export side has been made.
 
  * "git push $there $src:$dst" rejects when $dst is not a fully
-   qualified refname and not clear what the end user meant.  The
+   qualified refname and it is not clear what the end user meant.  The
    codepath has been taught to give a clearer error message, and also
    guess where the push should go by taking the type of the pushed
    object into account (e.g. a tag object would want to go under
@@ -77,9 +77,9 @@ UI, Workflows & Features
 
  * A new date format "--date=human" that morphs its output depending
    on how far the time is from the current time has been introduced.
-   "--date=auto" can be used to use this new format when the output is
-   going to the pager or to the terminal and otherwise the default
-   format.
+   "--date=auto:human" can be used to use this new format (or any
+   existing format) when the output is going to the pager or to the
+   terminal, and otherwise the default format.
 
 
 Performance, Internal Implementation, Development Support etc.
@@ -88,7 +88,7 @@ Performance, Internal Implementation, Development Support etc.
    (non-)existence of loose objects.
 
  * More codepaths have become aware of working with in-core repository
-   instance other than the default "the_repository".
+   instances other than the default "the_repository".
 
  * The "strncat()" function is now among the banned functions.
 
@@ -125,13 +125,13 @@ Performance, Internal Implementation, Development Support etc.
  * The in-core repository instances are passed through more codepaths.
 
  * Update the protocol message specification to allow only the limited
-   use of scaled quantities.  This is ensure potential compatibility
-   issues will not go out of hand.
+   use of scaled quantities.  This is to ensure potential compatibility
+   issues will not get out of hand.
 
  * Micro-optimize the code that prepares commit objects to be walked
    by "git rev-list" when the commit-graph is available.
 
- * "git fetch" and "git upload-pack" learned to send all exchange over
+ * "git fetch" and "git upload-pack" learned to send all exchanges over
    the sideband channel while talking the v2 protocol.
 
  * The codepath to write out commit-graph has been optimized by
@@ -180,6 +180,13 @@ Performance, Internal Implementation, Development Support etc.
 
  * A flakey "p4" test has been removed.
 
+ * The code and tests assume that the system supplied iconv() would
+   always use BOM in its output when asked to encode to UTF-16 (or
+   UTF-32), but apparently some implementations output big-endian
+   without BOM.  A compile-time knob has been added to help such
+   systems (e.g. NonStop) to add BOM to the output to increase
+   portability.
+
 
 Fixes since v2.20
 -----------------
@@ -439,3 +446,6 @@ Fixes since v2.20
    (merge 2e285e7803 tz/gpg-test-fix later to maint).
    (merge 5427de960b kl/pretty-doc-markup-fix later to maint).
    (merge 3815f64b0d js/mingw-host-cpu later to maint).
+   (merge 5fe81438b5 rj/sequencer-sign-off-header-static later to maint).
+   (merge 18a4f6be6b nd/fileno-may-be-macro later to maint).
+   (merge 99e9ab54ab kd/t0028-octal-del-is-377-not-777 later to maint).
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index daa16403ec..5629ba4c5d 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -529,7 +529,6 @@ are incompatible with the following options:
  * --interactive
  * --exec
  * --keep-empty
- * --autosquash
  * --edit-todo
  * --root when used in combination with --onto
 
@@ -554,8 +553,6 @@ commit started empty (had no changes relative to its parent to
 start with) or ended empty (all changes were already applied
 upstream in other commits).
 
-The merge backend does the same.
-
 The interactive backend drops commits by default that
 started empty and halts if it hits a commit that ended up empty.
 The `--keep-empty` option exists for the interactive backend to allow
diff --git a/Makefile b/Makefile
index 0e13a5b469..f0b2299172 100644
--- a/Makefile
+++ b/Makefile
@@ -259,6 +259,10 @@ all::
 # Define OLD_ICONV if your library has an old iconv(), where the second
 # (input buffer pointer) parameter is declared with type (const char **).
 #
+# Define ICONV_OMITS_BOM if your iconv implementation does not write a
+# byte-order mark (BOM) when writing UTF-16 or UTF-32 and always writes in
+# big-endian format.
+#
 # Define NO_DEFLATE_BOUND if your zlib does not have deflateBound.
 #
 # Define NO_R_TO_GCC_LINKER if your gcc does not like "-R/path/lib"
@@ -433,6 +437,8 @@ all::
 #
 # Define HAVE_GETDELIM if your system has the getdelim() function.
 #
+# Define FILENO_IS_A_MACRO if fileno() is a macro, not a real function.
+#
 # Define PAGER_ENV to a SP separated VAR=VAL pairs to define
 # default environment variables to be passed when a pager is spawned, e.g.
 #
@@ -1415,6 +1421,9 @@ ifndef NO_ICONV
 		EXTLIBS += $(ICONV_LINK) -liconv
 	endif
 endif
+ifdef ICONV_OMITS_BOM
+	BASIC_CFLAGS += -DICONV_OMITS_BOM
+endif
 ifdef NEEDS_LIBGEN
 	EXTLIBS += -lgen
 endif
@@ -1800,6 +1809,11 @@ ifdef HAVE_WPGMPTR
 	BASIC_CFLAGS += -DHAVE_WPGMPTR
 endif
 
+ifdef FILENO_IS_A_MACRO
+	COMPAT_CFLAGS += -DFILENO_IS_A_MACRO
+	COMPAT_OBJS += compat/fileno.o
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index c1cff32661..e7325fe37f 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -173,7 +173,7 @@ static int bisect_reset(const char *commit)
 			argv_array_clear(&argv);
 			return error(_("could not check out original"
 				       " HEAD '%s'. Try 'git bisect"
-				       "reset <commit>'."), branch.buf);
+				       " reset <commit>'."), branch.buf);
 		}
 		argv_array_clear(&argv);
 	}
@@ -646,7 +646,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "no-checkout", &no_checkout,
 			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_BOOL(0, "no-log", &nolog,
-			 N_("no log for BISECT_WRITE ")),
+			 N_("no log for BISECT_WRITE")),
 		OPT_END()
 	};
 	struct bisect_terms terms = { .term_good = NULL, .term_bad = NULL };
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 5a09fe24cd..b620fd54b4 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1480,7 +1480,7 @@ static inline void fetch_one_setup_partial(struct remote *remote)
 	if (strcmp(remote->name, repository_format_partial_clone)) {
 		if (filter_options.choice)
 			die(_("--filter can only be used with the remote "
-			      "configured in extensions.partialclone"));
+			      "configured in extensions.partialClone"));
 		return;
 	}
 
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 96efd40901..7c7bc13e91 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1434,7 +1434,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	}
 
 	if (options.reschedule_failed_exec && !is_interactive(&options))
-		die(_("--reschedule-failed-exec requires an interactive rebase"));
+		die(_("%s requires an interactive rebase"), "--reschedule-failed-exec");
 
 	if (options.git_am_opts.argc) {
 		/* all am options except -q are compatible only with --am */
diff --git a/compat/fileno.c b/compat/fileno.c
new file mode 100644
index 0000000000..7b105f4cd7
--- /dev/null
+++ b/compat/fileno.c
@@ -0,0 +1,7 @@
+#define COMPAT_CODE
+#include "../git-compat-util.h"
+
+int git_fileno(FILE *stream)
+{
+	return fileno(stream);
+}
diff --git a/compat/mingw.h b/compat/mingw.h
index 98407744f2..30d9fb3e36 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -6,25 +6,6 @@ typedef _sigset_t sigset_t;
 #include <winsock2.h>
 #include <ws2tcpip.h>
 
-#ifdef __MINGW64_VERSION_MAJOR
-/*
- * In Git for Windows, we cannot rely on `uname -m` to report the correct
- * architecture: /usr/bin/uname.exe will report the architecture with which the
- * current MSYS2 runtime was built, not the architecture for which we are
- * currently compiling (both 32-bit and 64-bit `git.exe` is built in the 64-bit
- * Git for Windows SDK).
- */
-#undef GIT_HOST_CPU
-/* This was figured out by looking at `cpp -dM </dev/null`'s output */
-#if defined(__x86_64__)
-#define GIT_HOST_CPU "x86_64"
-#elif defined(__i686__)
-#define GIT_HOST_CPU "i686"
-#else
-#error "Unknown architecture"
-#endif
-#endif
-
 /* MinGW-w64 reports to have flockfile, but it does not actually have it. */
 #ifdef __MINGW64_VERSION_MAJOR
 #undef _POSIX_THREAD_SAFE_FUNCTIONS
diff --git a/config.mak.uname b/config.mak.uname
index 786bb2f913..b37fa8424c 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -221,6 +221,7 @@ ifeq ($(uname_S),FreeBSD)
 	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
 	PAGER_ENV = LESS=FRX LV=-c MORE=FRX
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	FILENO_IS_A_MACRO = UnfortunatelyYes
 endif
 ifeq ($(uname_S),OpenBSD)
 	NO_STRCASESTR = YesPlease
@@ -234,6 +235,7 @@ ifeq ($(uname_S),OpenBSD)
 	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
 	PROCFS_EXECUTABLE_PATH = /proc/curproc/file
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	FILENO_IS_A_MACRO = UnfortunatelyYes
 endif
 ifeq ($(uname_S),MirBSD)
 	NO_STRCASESTR = YesPlease
@@ -490,6 +492,7 @@ ifeq ($(uname_S),NONSTOP_KERNEL)
 	OLD_ICONV = UnfortunatelyYes
 	NO_REGEX = NeedsStartEnd
 	NO_PTHREADS = UnfortunatelyYes
+	FREAD_READS_DIRECTORIES = UnfortunatelyYes
 
 	# Not detected (nor checked for) by './configure'.
 	# We don't have SA_RESTART on NonStop, unfortunalety.
@@ -507,9 +510,7 @@ ifeq ($(uname_S),NONSTOP_KERNEL)
 	# RFE 10-120912-4693 submitted to HP NonStop development.
 	NO_SETITIMER = UnfortunatelyYes
 	SANE_TOOL_PATH = /usr/coreutils/bin:/usr/local/bin
-	SHELL_PATH = /usr/local/bin/bash
-	# as of H06.25/J06.14, we might better use this
-	#SHELL_PATH = /usr/coreutils/bin/bash
+	SHELL_PATH = /usr/coreutils/bin/bash
 endif
 ifneq (,$(findstring MINGW,$(uname_S)))
 	pathsep = ;
@@ -571,9 +572,11 @@ else
 		prefix = /usr/
 		ifeq (MINGW32,$(MSYSTEM))
 			prefix = /mingw32
+			HOST_CPU = i686
 		endif
 		ifeq (MINGW64,$(MSYSTEM))
 			prefix = /mingw64
+			HOST_CPU = x86_64
 		else
 			COMPAT_CFLAGS += -D_USE_32BIT_TIME_T
 			BASIC_LDFLAGS += -Wl,--large-address-aware
diff --git a/git-compat-util.h b/git-compat-util.h
index 29a19902aa..6573808ebd 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1234,6 +1234,14 @@ struct tm *git_gmtime_r(const time_t *, struct tm *);
 #define getc_unlocked(fh) getc(fh)
 #endif
 
+#ifdef FILENO_IS_A_MACRO
+int git_fileno(FILE *stream);
+# ifndef COMPAT_CODE
+#  undef fileno
+#  define fileno(p) git_fileno(p)
+# endif
+#endif
+
 /*
  * Our code often opens a path to an optional file, to work on its
  * contents when we can successfully open it.  We can ignore a failure
diff --git a/imap-send.c b/imap-send.c
index 18ca6ba10a..6c54d8c29d 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -1114,7 +1114,7 @@ static struct imap_store *imap_open_store(struct imap_server_conf *srvc, char *f
 
 			if (!strcmp(srvc->auth_method, "CRAM-MD5")) {
 				if (!CAP(AUTH_CRAM_MD5)) {
-					fprintf(stderr, "You specified"
+					fprintf(stderr, "You specified "
 						"CRAM-MD5 as authentication method, "
 						"but %s doesn't support it.\n", srvc->host);
 					goto bail;
diff --git a/sequencer.c b/sequencer.c
index 972402e8c0..0db410d590 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -35,7 +35,7 @@
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
-const char sign_off_header[] = "Signed-off-by: ";
+static const char sign_off_header[] = "Signed-off-by: ";
 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
 
 GIT_PATH_FUNC(git_path_commit_editmsg, "COMMIT_EDITMSG")
diff --git a/sequencer.h b/sequencer.h
index 93e891309b..4d505b3590 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -107,8 +107,6 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
 		    unsigned autosquash);
 int rearrange_squash(struct repository *r);
 
-extern const char sign_off_header[];
-
 /*
  * Append a signoff to the commit message in "msgbuf". The ignore_footer
  * parameter specifies the number of bytes at the end of msgbuf that should
diff --git a/sha1-name.c b/sha1-name.c
index d1cc77c124..6dda2c16df 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1820,9 +1820,11 @@ void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
 			       prefix, &oid, &oc);
 }
 
-int get_oid_with_context(struct repository *repo, const char *str,
-			 unsigned flags, struct object_id *oid,
-			 struct object_context *oc)
+enum get_oid_result get_oid_with_context(struct repository *repo,
+					 const char *str,
+					 unsigned flags,
+					 struct object_id *oid,
+					 struct object_context *oc)
 {
 	if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
 		BUG("incompatible flags for get_sha1_with_context");
diff --git a/t/README b/t/README
index 1326fd7505..886bbec5bc 100644
--- a/t/README
+++ b/t/README
@@ -211,6 +211,11 @@ appropriately before running "make".
 	'.stress-<nr>' suffix, and the trash directory of the failed
 	test job is renamed to end with a '.stress-failed' suffix.
 
+--stress-limit=<N>::
+	When combined with --stress run the test script repeatedly
+	this many times in each of the parallel jobs or until one of
+	them fails, whichever comes first.
+
 You can also set the GIT_TEST_INSTALLED environment variable to
 the bindir of an existing git installation to test that installation.
 You still need to have built this git sandbox, from which various
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index 216281eabc..0dfb48c2f6 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -91,6 +91,7 @@ HTTPD_DOCUMENT_ROOT_PATH=$HTTPD_ROOT_PATH/www
 # hack to suppress apache PassEnv warnings
 GIT_VALGRIND=$GIT_VALGRIND; export GIT_VALGRIND
 GIT_VALGRIND_OPTIONS=$GIT_VALGRIND_OPTIONS; export GIT_VALGRIND_OPTIONS
+GIT_TEST_SIDEBAND_ALL=$GIT_TEST_SIDEBAND_ALL; export GIT_TEST_SIDEBAND_ALL
 GIT_TRACE=$GIT_TRACE; export GIT_TRACE
 
 if ! test -x "$LIB_HTTPD_PATH"
diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh
index e58ecbfc44..1090e650ed 100755
--- a/t/t0028-working-tree-encoding.sh
+++ b/t/t0028-working-tree-encoding.sh
@@ -6,6 +6,30 @@ test_description='working-tree-encoding conversion via gitattributes'
 
 GIT_TRACE_WORKING_TREE_ENCODING=1 && export GIT_TRACE_WORKING_TREE_ENCODING
 
+test_lazy_prereq NO_UTF16_BOM '
+	test $(printf abc | iconv -f UTF-8 -t UTF-16 | wc -c) = 6
+'
+
+test_lazy_prereq NO_UTF32_BOM '
+	test $(printf abc | iconv -f UTF-8 -t UTF-32 | wc -c) = 12
+'
+
+write_utf16 () {
+	if test_have_prereq NO_UTF16_BOM
+	then
+		printf '\xfe\xff'
+	fi &&
+	iconv -f UTF-8 -t UTF-16
+}
+
+write_utf32 () {
+	if test_have_prereq NO_UTF32_BOM
+	then
+		printf '\x00\x00\xfe\xff'
+	fi &&
+	iconv -f UTF-8 -t UTF-32
+}
+
 test_expect_success 'setup test files' '
 	git config core.eol lf &&
 
@@ -13,8 +37,8 @@ test_expect_success 'setup test files' '
 	echo "*.utf16 text working-tree-encoding=utf-16" >.gitattributes &&
 	echo "*.utf16lebom text working-tree-encoding=UTF-16LE-BOM" >>.gitattributes &&
 	printf "$text" >test.utf8.raw &&
-	printf "$text" | iconv -f UTF-8 -t UTF-16 >test.utf16.raw &&
-	printf "$text" | iconv -f UTF-8 -t UTF-32 >test.utf32.raw &&
+	printf "$text" | write_utf16 >test.utf16.raw &&
+	printf "$text" | write_utf32 >test.utf32.raw &&
 	printf "\377\376"                         >test.utf16lebom.raw &&
 	printf "$text" | iconv -f UTF-8 -t UTF-32LE >>test.utf16lebom.raw &&
 
@@ -25,12 +49,12 @@ test_expect_success 'setup test files' '
 	# BOM tests
 	printf "\0a\0b\0c"                         >nobom.utf16be.raw &&
 	printf "a\0b\0c\0"                         >nobom.utf16le.raw &&
-	printf "\376\777\0a\0b\0c"                 >bebom.utf16be.raw &&
-	printf "\777\376a\0b\0c\0"                 >lebom.utf16le.raw &&
+	printf "\376\377\0a\0b\0c"                 >bebom.utf16be.raw &&
+	printf "\377\376a\0b\0c\0"                 >lebom.utf16le.raw &&
 	printf "\0\0\0a\0\0\0b\0\0\0c"             >nobom.utf32be.raw &&
 	printf "a\0\0\0b\0\0\0c\0\0\0"             >nobom.utf32le.raw &&
-	printf "\0\0\376\777\0\0\0a\0\0\0b\0\0\0c" >bebom.utf32be.raw &&
-	printf "\777\376\0\0a\0\0\0b\0\0\0c\0\0\0" >lebom.utf32le.raw &&
+	printf "\0\0\376\377\0\0\0a\0\0\0b\0\0\0c" >bebom.utf32be.raw &&
+	printf "\377\376\0\0a\0\0\0b\0\0\0c\0\0\0" >lebom.utf32le.raw &&
 
 	# Add only UTF-16 file, we will add the UTF-32 file later
 	cp test.utf16.raw test.utf16 &&
@@ -124,8 +148,8 @@ do
 		test_when_finished "rm -f crlf.utf${i}.raw lf.utf${i}.raw" &&
 		test_when_finished "git reset --hard HEAD^" &&
 
-		cat lf.utf8.raw | iconv -f UTF-8 -t UTF-${i} >lf.utf${i}.raw &&
-		cat crlf.utf8.raw | iconv -f UTF-8 -t UTF-${i} >crlf.utf${i}.raw &&
+		cat lf.utf8.raw | write_utf${i} >lf.utf${i}.raw &&
+		cat crlf.utf8.raw | write_utf${i} >crlf.utf${i}.raw &&
 		cp crlf.utf${i}.raw eol.utf${i} &&
 
 		cat >expectIndexLF <<-EOF &&
@@ -223,7 +247,7 @@ test_expect_success ICONV_SHIFT_JIS 'check roundtrip encoding' '
 
 	text="hallo there!\nroundtrip test here!" &&
 	printf "$text" | iconv -f UTF-8 -t SHIFT-JIS >roundtrip.shift &&
-	printf "$text" | iconv -f UTF-8 -t UTF-16 >roundtrip.utf16 &&
+	printf "$text" | write_utf16 >roundtrip.utf16 &&
 	echo "*.shift text working-tree-encoding=SHIFT-JIS" >>.gitattributes &&
 
 	# SHIFT-JIS encoded files are round-trip checked by default...
diff --git a/t/t1404-update-ref-errors.sh b/t/t1404-update-ref-errors.sh
index 51a4f4c0ac..6b6a8e2292 100755
--- a/t/t1404-update-ref-errors.sh
+++ b/t/t1404-update-ref-errors.sh
@@ -614,7 +614,7 @@ test_expect_success 'delete fails cleanly if packed-refs file is locked' '
 	test_when_finished "rm -f .git/packed-refs.lock" &&
 	test_must_fail git update-ref -d $prefix/foo >out 2>err &&
 	git for-each-ref $prefix >actual &&
-	test_i18ngrep "Unable to create $Q.*packed-refs.lock$Q: File exists" err &&
+	test_i18ngrep "Unable to create $Q.*packed-refs.lock$Q: " err &&
 	test_cmp unchanged actual
 '
 
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 52fa41c707..b60b11f9f2 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -149,10 +149,12 @@ test_expect_success 'rebase -i with the exec command checks tree cleanness' '
 
 test_expect_success 'rebase -x with empty command fails' '
 	test_when_finished "git rebase --abort ||:" &&
-	test_must_fail git rebase -x "" @ 2>actual &&
+	test_must_fail env GIT_TEST_REBASE_USE_BUILTIN=true \
+		git rebase -x "" @ 2>actual &&
 	test_write_lines "error: empty exec command" >expected &&
 	test_i18ncmp expected actual &&
-	test_must_fail git rebase -x " " @ 2>actual &&
+	test_must_fail env GIT_TEST_REBASE_USE_BUILTIN=true \
+		git rebase -x " " @ 2>actual &&
 	test_i18ncmp expected actual
 '
 
@@ -160,7 +162,8 @@ LF='
 '
 test_expect_success 'rebase -x with newline in command fails' '
 	test_when_finished "git rebase --abort ||:" &&
-	test_must_fail git rebase -x "a${LF}b" @ 2>actual &&
+	test_must_fail env GIT_TEST_REBASE_USE_BUILTIN=true \
+		git rebase -x "a${LF}b" @ 2>actual &&
 	test_write_lines "error: exec commands cannot contain newlines" \
 			 >expected &&
 	test_i18ncmp expected actual
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 16d10ebce8..d4bd1522fe 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -383,7 +383,7 @@ corrupt_graph_and_verify() {
 	cp $objdir/info/commit-graph commit-graph-backup &&
 	printf "$data" | dd of="$objdir/info/commit-graph" bs=1 seek="$pos" conv=notrunc &&
 	dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=0 &&
-	dd if=/dev/zero of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=$(($orig_size - $zero_pos)) &&
+	generate_zero_bytes $(($orig_size - $zero_pos)) >>"$objdir/info/commit-graph" &&
 	test_must_fail git commit-graph verify 2>test_err &&
 	grep -v "^+" test_err >err &&
 	test_i18ngrep "$grepstr" err
diff --git a/t/t5562-http-backend-content-length.sh b/t/t5562-http-backend-content-length.sh
index 90d890d02f..bbadde2c6e 100755
--- a/t/t5562-http-backend-content-length.sh
+++ b/t/t5562-http-backend-content-length.sh
@@ -143,14 +143,14 @@ test_expect_success GZIP 'push gzipped empty' '
 
 test_expect_success 'CONTENT_LENGTH overflow ssite_t' '
 	NOT_FIT_IN_SSIZE=$(ssize_b100dots) &&
-	env \
+	generate_zero_bytes infinity  | env \
 		CONTENT_TYPE=application/x-git-upload-pack-request \
 		QUERY_STRING=/repo.git/git-upload-pack \
 		PATH_TRANSLATED="$PWD"/.git/git-upload-pack \
 		GIT_HTTP_EXPORT_ALL=TRUE \
 		REQUEST_METHOD=POST \
 		CONTENT_LENGTH="$NOT_FIT_IN_SSIZE" \
-		git http-backend </dev/zero >/dev/null 2>err &&
+		git http-backend >/dev/null 2>err &&
 	grep "fatal:.*CONTENT_LENGTH" err
 '
 
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 92cf8f812c..094c07748a 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -116,6 +116,19 @@ remove_cr () {
 	tr '\015' Q | sed -e 's/Q$//'
 }
 
+# Generate an output of $1 bytes of all zeroes (NULs, not ASCII zeroes).
+# If $1 is 'infinity', output forever or until the receiving pipe stops reading,
+# whichever comes first.
+generate_zero_bytes () {
+	perl -e 'if ($ARGV[0] == "infinity") {
+		while (-1) {
+			print "\0"
+		}
+	} else {
+		print "\0" x $ARGV[0]
+	}' "$@"
+}
+
 # In some bourne shell implementations, the "unset" builtin returns
 # nonzero status when a variable to be unset was not set in the first
 # place.
@@ -1289,7 +1302,7 @@ test_set_port () {
 			port=$(($port + 10000))
 		fi
 		;;
-	*[^0-9]*|0*)
+	*[!0-9]*|0*)
 		error >&7 "invalid port number: $port"
 		;;
 	*)
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 42b1a0aa7f..8665b0a9b6 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -149,7 +149,7 @@ do
 	--stress=*)
 		stress=${opt#--*=}
 		case "$stress" in
-		*[^0-9]*|0*|"")
+		*[!0-9]*|0*|"")
 			echo "error: --stress=<N> requires the number of jobs to run" >&2
 			exit 1
 			;;
@@ -157,6 +157,17 @@ do
 			;;
 		esac
 		;;
+	--stress-limit=*)
+		stress_limit=${opt#--*=}
+		case "$stress_limit" in
+		*[!0-9]*|0*|"")
+			echo "error: --stress-limit=<N> requires the number of repetitions" >&2
+			exit 1
+			;;
+		*)	# Good.
+			;;
+		esac
+		;;
 	*)
 		echo "error: unknown test option '$opt'" >&2; exit 1 ;;
 	esac
@@ -242,8 +253,10 @@ then
 				exit 1
 			' TERM INT
 
-			cnt=0
-			while ! test -e "$stressfail"
+			cnt=1
+			while ! test -e "$stressfail" &&
+			      { test -z "$stress_limit" ||
+				test $cnt -le $stress_limit ; }
 			do
 				$TEST_SHELL_PATH "$0" "$@" >"$TEST_RESULTS_BASE.stress-$job_nr.out" 2>&1 &
 				test_pid=$!
@@ -266,6 +279,7 @@ then
 
 	if test -f "$stressfail"
 	then
+		stress_exit=1
 		echo "Log(s) of failed test run(s):"
 		for failed_job_nr in $(sort -n "$stressfail")
 		do
diff --git a/utf8.c b/utf8.c
index 83824dc2f4..3b42fadffd 100644
--- a/utf8.c
+++ b/utf8.c
@@ -559,6 +559,10 @@ char *reencode_string_len(const char *in, size_t insz,
 	/*
 	 * For writing, UTF-16 iconv typically creates "UTF-16BE-BOM"
 	 * Some users under Windows want the little endian version
+	 *
+	 * We handle UTF-16 and UTF-32 ourselves only if the platform does not
+	 * provide a BOM (which we require), since we want to match the behavior
+	 * of the system tools and libc as much as possible.
 	 */
 	if (same_utf_encoding("UTF-16LE-BOM", out_encoding)) {
 		bom_str = utf16_le_bom;
@@ -568,6 +572,16 @@ char *reencode_string_len(const char *in, size_t insz,
 		bom_str = utf16_be_bom;
 		bom_len = sizeof(utf16_be_bom);
 		out_encoding = "UTF-16BE";
+#ifdef ICONV_OMITS_BOM
+	} else if (same_utf_encoding("UTF-16", out_encoding)) {
+		bom_str = utf16_be_bom;
+		bom_len = sizeof(utf16_be_bom);
+		out_encoding = "UTF-16BE";
+	} else if (same_utf_encoding("UTF-32", out_encoding)) {
+		bom_str = utf32_be_bom;
+		bom_len = sizeof(utf32_be_bom);
+		out_encoding = "UTF-32BE";
+#endif
 	}
 
 	conv = iconv_open(out_encoding, in_encoding);