Prep new release 1.18.0

- Rebuild with newer Cython (incl. setting language_level)
- Update build chain with latest autotools
- Fixes include:
  - Update mIV_IF_TYPE
  - intf_loop aliases fixes
  - Fix bug that caused Nmap to fail find any network intf
  - Fix bug with interface indexes > 255
  - Fixed conflicting struct names in BSD and Linux
  - Prio to IFF_LOOPBACK flag when setting intf type
  - A few comp warnings eliminated
  - Small test updates

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.14)
 
-project(dnet VERSION 1.17.0 LANGUAGES C)
+project(dnet VERSION 1.18.0 LANGUAGES C)
 
 find_package(TCL)
 

Makefile.in

@@ -257,7 +257,6 @@ CHECKINC = @CHECKINC@
 CHECKLIB = @CHECKLIB@
 CHECK_CFLAGS = @CHECK_CFLAGS@
 CHECK_LIBS = @CHECK_LIBS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
 CSCOPE = @CSCOPE@
 CTAGS = @CTAGS@

aclocal.m4

@@ -14,8 +14,8 @@
 m4_ifndef([AC_CONFIG_MACRO_DIRS], [m4_defun([_AM_CONFIG_MACRO_DIRS], [])m4_defun([AC_CONFIG_MACRO_DIRS], [_AM_CONFIG_MACRO_DIRS($@)])])
 m4_ifndef([AC_AUTOCONF_VERSION],
   [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
-m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.71],,
-[m4_warning([this file was generated for autoconf 2.71.
+m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.72],,
+[m4_warning([this file was generated for autoconf 2.72.
 You have another version of autoconf.  It may work, but is not guaranteed to.
 If you have problems, you may need to regenerate the build system entirely.
 To do so, use the procedure documented by the package, typically 'autoreconf'.])])