autoconf: use include directives instead of recursing down cmd

No installation diff, dist lost
  -zfs-2.1.99/cmd/fsck_zfs/fsck.zfs
which was distributed erroneously, since it's generated

Also clean gitrev on clean

Also add -e 'any possible bashisms' to default checkbashisms flags,
and fully parallelise it and shellcheck, and it works out-of-tree, too

Also align the Release in the dist META file correctly

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13316

cmd/zstream/.gitignore

@@ -1 +0,0 @@
-zstream

cmd/zstream/Makefile.am

@@ -1,21 +1,18 @@
-include $(top_srcdir)/config/Rules.am
-
-sbin_PROGRAMS = zstream
-
-zstream_SOURCES = \
-	zstream.c \
-	zstream.h \
-	zstream_dump.c \
-	zstream_redup.c \
-	zstream_token.c
-
-zstream_LDADD = \
-	$(abs_top_builddir)/libzfs.la \
-	$(abs_top_builddir)/libzfs_core.la \
-	$(abs_top_builddir)/libnvpair.la
-
-include $(top_srcdir)/config/CppCheck.am
+sbin_PROGRAMS   += zstream
 CPPCHECKTARGETS += zstream
 
+zstream_SOURCES = \
+	%D%/zstream.c \
+	%D%/zstream.h \
+	%D%/zstream_dump.c \
+	%D%/zstream_redup.c \
+	%D%/zstream_token.c
+
+zstream_LDADD = \
+	libzfs.la \
+	libzfs_core.la \
+	libnvpair.la
+
+PHONY += install-exec-hook
 install-exec-hook:
 	cd $(DESTDIR)$(sbindir) && $(LN_S) -f zstream zstreamdump