--- rxvt-unicode/configure.ac	2015/06/16 11:58:26	1.153
+++ rxvt-unicode/configure.ac	2021/07/23 19:18:52	1.157
@@ -3,9 +3,9 @@
 dnl#
 
 AC_INIT
-AC_PREREQ(2.50)
+AC_PREREQ(2.71)
 AC_CONFIG_SRCDIR([src/feature.h])
-AC_CONFIG_HEADER(config.h:config.h.in)
+AC_CONFIG_HEADERS(config.h:config.h.in)
 
 AC_CANONICAL_HOST
 
@@ -28,11 +28,13 @@
 AC_PROG_CXX
 AC_PROG_INSTALL
 
-AC_AIX
-AC_GNU_SOURCE
-AC_ISC_POSIX
+AC_USE_SYSTEM_EXTENSIONS
 AC_LANG(C++)
 
+if test "$ac_prog_cxx_stdcxx" != cxx11; then
+  AC_MSG_ERROR([the compiler does not support C++11])
+fi
+
 LINKER="$CXX"
 dnl check whether we can link with gcc -lsupc++
 if test x$GCC = xyes && test x$GXX = xyes; then
@@ -295,10 +297,11 @@
     AC_DEFINE(NO_DELETE_KEY, 1, Define if you don't want support for the (non-keypad) delete key)
   fi])
 
+support_resources=yes
 AC_ARG_ENABLE(resources,
   [  --disable-resources     disable all resource checking],
   [if test x$enableval = xno; then
-    AC_DEFINE(NO_RESOURCES, 1, Define if you don't want any resources read)
+    support_resources=no
   fi])
 
 AC_ARG_ENABLE(8bitctrls,
@@ -412,6 +415,14 @@
     AC_DEFINE_UNQUOTED(RXVT_TERMINFO, "$withval", Set TERMINFO value to the value given by configure) terminfo="$withval"
   fi])
 
+if test x$support_resources = xno; then
+  if test x$support_frills = xyes || test x$support_perl = xyes; then
+    AC_MSG_ERROR([--disable-resources requires --disable-frills --disable-perl])
+  fi
+
+  AC_DEFINE(NO_RESOURCES, 1, Define if you don't want any resources read)
+fi
+
 dnl# --------------------------------------------------------------------------
 
 LIBEV_M4_AVOID_LIBRT=1
@@ -425,6 +436,13 @@
 
 AC_PATH_TOOL(PKG_CONFIG, pkg-config, no)
 
+RXVT_CHECK_MODULES([PTYTTY], [libptytty], [:], [
+  AC_MSG_ERROR([unable to find libptytty])
+])
+
+AC_SUBST(PTYTTY_CFLAGS)
+AC_SUBST(PTYTTY_LIBS)
+
 image_lib=none
 
 PIXBUF_CFLAGS=
@@ -504,8 +522,6 @@
 dnl# --------------------------------------------------------------------------
 AC_CHECK_FUNCS(unsetenv)
 
-UTMP_CHECK
-
 dnl# --------------------------------------------------------------------------
 
 dnl# --------------------------------------------------------------------------
@@ -564,12 +580,6 @@
   AC_DEFINE(HAVE_NL_LANGINFO, 1, Define if nl_langinfo(CODESET) works)
 fi
 
-SCM_RIGHTS_CHECK
-
-PTY_CHECK
-
-TTY_GROUP_CHECK
-
 dnl# --------------------------------------------------------------------------
 dnl# now add and remove other stuff
 dnl# --------------------------------------------------------------------------