--- a/configure.ac	Mon Feb 26 22:43:12 2018 +0800
+++ b/configure.ac	Sun Mar 04 15:07:09 2018 +0800
@@ -9,6 +9,13 @@
 AC_INIT
 AC_CONFIG_SRCDIR(buffer.c)
 
+# Record which revision is being built
+if test -s "`which hg`" && test -d "$srcdir/.hg"; then
+	hgrev=`hg id -i -R "$srcdir"`
+	AC_MSG_NOTICE([Source directory Mercurial base revision $hgrev])
+fi
+
+ORIGCFLAGS="$CFLAGS"
 # Checks for programs.
 AC_PROG_CC
 
@@ -29,7 +36,7 @@
 }])
 
 # set compile flags prior to other tests
-if test -z "$OLDCFLAGS" && test "$GCC" = "yes"; then
+if test -z "$ORIGCFLAGS" && test "$GCC" = "yes"; then
 	AC_MSG_NOTICE(No \$CFLAGS set... using "-Os -W -Wall" for GCC)
 	CFLAGS="-Os -W -Wall"
 fi
@@ -315,14 +322,28 @@
 		AC_MSG_NOTICE(Using shadow passwords if available)
 	]
 )
-			
+
+AC_ARG_ENABLE(fuzz,
+	[  --enable-fuzz           Build fuzzing. Not recommended for deployment.],
+	[
+		AC_DEFINE(DROPBEAR_FUZZ, 1, Fuzzing)
+		AC_MSG_NOTICE(Enabling fuzzing)
+		DROPBEAR_FUZZ=1
+	],
+	[
+		AC_DEFINE(DROPBEAR_FUZZ, 0, Fuzzing)
+		DROPBEAR_FUZZ=0
+	]
+
+)
+AC_SUBST(DROPBEAR_FUZZ)
 
 # Checks for header files.
 AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
-AC_CHECK_HEADERS([fcntl.h limits.h netinet/in.h netinet/tcp.h stdlib.h \
-	string.h sys/socket.h sys/time.h termios.h unistd.h crypt.h \
-	pty.h ioctl.h libutil.h libgen.h inttypes.h stropts.h utmp.h \
+AC_CHECK_HEADERS([netinet/in.h netinet/tcp.h \
+	crypt.h \
+	pty.h libutil.h libgen.h inttypes.h stropts.h utmp.h \
 	utmpx.h lastlog.h paths.h util.h netdb.h security/pam_appl.h \
 	pam/pam_appl.h netinet/in_systm.h sys/uio.h linux/pkt_sched.h])
 
@@ -479,7 +500,6 @@
 
 AC_CHECK_FUNCS(explicit_bzero memset_s)
 
-
 AC_ARG_ENABLE(bundled-libtom,
 [  --enable-bundled-libtom       Force using bundled libtomcrypt/libtommath even if a system version exists.
   --disable-bundled-libtom      Force using system libtomcrypt/libtommath, fail if it does not exist.
@@ -775,7 +795,9 @@
 AC_PROG_GCC_TRADITIONAL
 AC_FUNC_MEMCMP
 AC_FUNC_SELECT_ARGTYPES
-AC_CHECK_FUNCS([dup2 getpass getspnam getusershell memset putenv select socket strdup clearenv strlcpy strlcat daemon basename _getpty getaddrinfo freeaddrinfo getnameinfo fork writev])
+AC_CHECK_FUNCS([getpass getspnam getusershell putenv])
+AC_CHECK_FUNCS([clearenv strlcpy strlcat daemon basename _getpty getaddrinfo ])
+AC_CHECK_FUNCS([freeaddrinfo getnameinfo fork writev getgrouplist])
 
 AC_SEARCH_LIBS(basename, gen, AC_DEFINE(HAVE_BASENAME))