diff --git a/src/auto/configure b/src/auto/configure
index 7fe5975..e9ee017 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -3449,6 +3449,97 @@
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
+$as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
+if ${ac_cv_prog_cc_c89+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_prog_cc_c89=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdarg.h>
+#include <stdio.h>
+struct stat;
+/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
+struct buf { int x; };
+FILE * (*rcsopen) (struct buf *, struct stat *, int);
+static char *e (p, i)
+     char **p;
+     int i;
+{
+  return p[i];
+}
+static char *f (char * (*g) (char **, int), char **p, ...)
+{
+  char *s;
+  va_list v;
+  va_start (v,p);
+  s = g (p, va_arg (v,int));
+  va_end (v);
+  return s;
+}
+
+/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+   function prototypes and stuff, but not '\xHH' hex character constants.
+   These don't provoke an error unfortunately, instead are silently treated
+   as 'x'.  The following induces an error, until -std is added to get
+   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
+   array size at least.  It's necessary to write '\x00'==0 to get something
+   that's true only with -std.  */
+int osf4_cc_array ['\x00' == 0 ? 1 : -1];
+
+/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+   inside strings and character constants.  */
+#define FOO(x) 'x'
+int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];
+
+int test (int i, double x);
+struct s1 {int (*f) (int a);};
+struct s2 {int (*f) (double a);};
+int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
+int argc;
+char **argv;
+int
+main ()
+{
+return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
+  ;
+  return 0;
+}
+_ACEOF
+for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std \
+	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_prog_cc_c89=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext
+  test "x$ac_cv_prog_cc_c89" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+
+fi
+# AC_CACHE_VAL
+case "x$ac_cv_prog_cc_c89" in
+  x)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+$as_echo "none needed" >&6; } ;;
+  xno)
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+$as_echo "unsupported" >&6; } ;;
+  *)
+    CC="$CC $ac_cv_prog_cc_c89"
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
+$as_echo "$ac_cv_prog_cc_c89" >&6; } ;;
+esac
+if test "x$ac_cv_prog_cc_c89" != xno; then :
+
+fi
+
 		ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -4115,6 +4206,8 @@
       CFLAGS="$CFLAGS -fno-strength-reduce"
     fi
   fi
+
+    CPPFLAGS="$CPPFLAGS -D_POSIX_C_SOURCE=200809L -D_XOPEN_SOURCE=700"
 fi
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for clang version" >&5
@@ -4187,7 +4280,7 @@
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
   MACOS_X=yes
-  CPPFLAGS="$CPPFLAGS -DMACOS_X"
+  CPPFLAGS="$CPPFLAGS -D_DARWIN_C_SOURCE -DMACOS_X"
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking --disable-darwin argument" >&5
 $as_echo_n "checking --disable-darwin argument... " >&6; }
@@ -14341,6 +14434,10 @@
 	CFLAGS="-D_ALL_SOURCE -Wc,float\(ieee\),dll"
 fi
 
+if test "$GCC" = yes -a "$GUITYPE" != "GTK"; then
+  CFLAGS="$CFLAGS -ansi"
+fi
+
 ac_config_files="$ac_config_files auto/config.mk:config.mk.in"
 
 cat >confcache <<\_ACEOF
diff --git a/src/channel.c b/src/channel.c
index a25e9fe..f5d86ed 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -672,9 +672,9 @@
     {
 	char		*p;
 
-	/* When using host->h_addr directly ubsan warns for it to not be
-	 * aligned.  First copy the pointer to aviod that. */
-	memcpy(&p, &host->h_addr, sizeof(p));
+	/* When using host->h_addr_list[0] directly ubsan warns for it to not
+	 * be aligned.  First copy the pointer to avoid that. */
+	memcpy(&p, &host->h_addr_list[0], sizeof(p));
 	memcpy((char *)&server.sin_addr, p, host->h_length);
     }
 
diff --git a/src/configure.ac b/src/configure.ac
index f2655a5..27309b2 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -11,7 +11,7 @@
 AC_PROG_MAKE_SET
 
 dnl Checks for programs.
-AC_PROG_CC		dnl required by almost everything
+AC_PROG_CC_C89		dnl required by almost everything
 AC_PROG_CPP		dnl required by header file checks
 AC_PROGRAM_EGREP	dnl required by AC_EGREP_CPP
 AC_PROG_FGREP		dnl finds working grep -F
@@ -61,6 +61,9 @@
       CFLAGS="$CFLAGS -fno-strength-reduce"
     fi
   fi
+
+  dnl Declare what standards the code should comply with
+  CPPFLAGS="$CPPFLAGS -D_POSIX_C_SOURCE=200809L -D_XOPEN_SOURCE=700"
 fi
 
 dnl clang-500.2.75 or around has abandoned -f[no-]strength-reduce and issues a
@@ -135,7 +138,7 @@
 if test "`(uname) 2>/dev/null`" = Darwin; then
   AC_MSG_RESULT(yes)
   MACOS_X=yes
-  CPPFLAGS="$CPPFLAGS -DMACOS_X"
+  CPPFLAGS="$CPPFLAGS -D_DARWIN_C_SOURCE -DMACOS_X"
 
   AC_MSG_CHECKING(--disable-darwin argument)
   AC_ARG_ENABLE(darwin,
@@ -4400,6 +4403,12 @@
 	CFLAGS="-D_ALL_SOURCE -Wc,float\(ieee\),dll"
 fi
 
+dnl Declare what standards the code should comply with.  But not when using
+dnl GTK, the header files cause all kinds of warnings.
+if test "$GCC" = yes -a "$GUITYPE" != "GTK"; then
+  CFLAGS="$CFLAGS -ansi"
+fi
+
 dnl write output files
 AC_OUTPUT(auto/config.mk:config.mk.in)
 
diff --git a/src/gui_gtk_x11.c b/src/gui_gtk_x11.c
index bb679bd..9c7e8d5 100644
--- a/src/gui_gtk_x11.c
+++ b/src/gui_gtk_x11.c
@@ -5607,15 +5607,17 @@
     guicolor_T
 gui_mch_get_color(char_u *name)
 {
+    guicolor_T color = INVALCOLOR;
+
     if (!gui.in_use)		/* can't do this when GUI not running */
-	return INVALCOLOR;
+	return color;
+
+    if (name != NULL)
+	color = gui_get_color_cmn(name);
 
 #if GTK_CHECK_VERSION(3,0,0)
-    return name != NULL ? gui_get_color_cmn(name) : INVALCOLOR;
+    return color;
 #else
-    guicolor_T color;
-
-    color = (name != NULL) ? gui_get_color_cmn(name) : INVALCOLOR;
     if (color == INVALCOLOR)
 	return INVALCOLOR;
 
diff --git a/src/if_python3.c b/src/if_python3.c
index b885deb..4360fe4 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -815,7 +815,7 @@
 #endif
     if (Py_IsInitialized())
     {
-	// acquire lock before finalizing
+	/* acquire lock before finalizing */
 	PyGILState_Ensure();
 
 	Py_Finalize();
diff --git a/src/version.c b/src/version.c
index 6bebac2..b24935f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1709,
+/**/
     1708,
 /**/
     1707,