cli: meson: Support building nmcli with libedit

After this change the nmcli program built with meson will have the
possibility to use libedit (BSD license) instead of libreadline
(GPLv3).

Meson configuration line:
meson configure -Dreadline=libedit -C ../nm-build/

or

meson --reconfigure -Dreadline=libedit ../nm-build/
ninja -C ../nm-build/

The new 'readline' option is set to 'auto' by default, so
the current behavior shall be preserved (and the libreadline is
used).

Two new config.h flags (always defined) have been introduced -
HAVE_EDITLINE_READLINE and HAVE_READLINE_HISTORY.

config.h.meson

@@ -255,3 +255,9 @@
 #mesondefine HAVE_PIDFD_OPEN
 #mesondefine HAVE_PIDFD_SEND_SIGNAL
 #mesondefine HAVE_RT_SIGQUEUEINFO
+
+/* Define to 1 if you want to use -ledit, otherwise 0 for default -lreadline. */
+#mesondefine HAVE_EDITLINE_READLINE
+
+/* Define to 1 if you have history support from -lreadline. */
+#mesondefine HAVE_READLINE_HISTORY

meson.build

@@ -733,24 +733,33 @@ if enable_concheck
 endif
 config_h.set10('WITH_CONCHECK', enable_concheck)
 
+config_h.set10('HAVE_READLINE_HISTORY', false)
+config_h.set10('HAVE_EDITLINE_READLINE', false)
+enable_readline = get_option('readline')
+if enable_readline != 'none'
+  if enable_readline == 'libreadline' or enable_readline == 'auto'
+    readline = cc.find_library('readline')
+    if readline.found()
+      readline_dep = declare_dependency(link_args: '-lreadline')
+      config_h.set10('HAVE_READLINE_HISTORY', true)
+    else
+      assert(enable_readline == 'auto', 'libreadline was not found')
+    endif
+  endif
+  if enable_readline == 'libedit' or (enable_readline == 'auto' and not readline.found())
+    edit = dependency('libedit')
+    if edit.found()
+      readline_dep = declare_dependency(link_args: '-ledit')
+      config_h.set10('HAVE_EDITLINE_READLINE', true)
+    else
+      assert(enable_readline == 'auto', 'libedit was not found')
+    endif
+  endif
+endif
+
 enable_nmcli = get_option('nmcli')
 if enable_nmcli
-  # FIXME: check for readline
+  assert(enable_readline != 'none', 'readline library with terminfo support is required (one of readline, edit, or editline, AND one of ncurses, curses, or termcap)')
-  # AX_LIB_READLINE
-  readline_dep = declare_dependency(link_args: '-lreadline')
-  '''
-  foreach readline_lib: ['-lreadline', '-ledit', '-leditline']
-    if not is_variable('readline_dep')
-      foreach termcap_lib: ['', '-lncurses', '-ltermcap', '-lcurses']
-        test_dep = declare_dependency(link_args: ' '.join([readline_lib, termcap_lib]))
-        if cc.has_function('readline', dependencies: test_dep) and cc.has_header('readline', dependencies: test_dep)
-          readline_dep = test_dep
-        endif
-      endforeach
-    endif
-  endforeach
-  '''
-  assert(readline_dep.found(), 'readline library with terminfo support is required (one of readline, edit, or editline, AND one of ncurses, curses, or termcap)')
 endif
 
 enable_nmtui = get_option('nmtui')
@@ -1086,4 +1095,5 @@ output += '  sanitizers: ' + get_option('b_sanitize') + '\n'
 output += '  Mozilla Public Suffix List: ' + enable_libpsl.to_string() + '\n'
 output += '  vapi: ' + enable_vapi.to_string() + '\n'
 output += '  ebpf: ' + enable_ebpf.to_string() + '\n'
+output += '  readline: ' + enable_readline + '\n'
 message(output)

meson_options.txt

@@ -72,3 +72,4 @@ option('ld_gc', type: 'boolean', value: true, description: 'Enable garbage colle
 option('libpsl', type: 'boolean', value: true, description: 'Link against libpsl')
 option('crypto', type: 'combo', choices: ['nss', 'gnutls'], value: 'nss', description: 'Cryptography library to use for certificate and key operations')
 option('qt', type: 'boolean', value: true, description: 'enable Qt examples')
+option('readline', type: 'combo', choices: ['auto', 'libreadline', 'libedit', 'none'], description: 'Using readline (auto) or libedit)')