[PULL 4/7] configure: fix backwards-compatibility for meson sphinx_build option

[Paolo Bonzini <pbonzini@redhat.com>]

Reintroduce the cmd_line.txt mangling to remove the sphinx_build option
when rerunning meson.  The mechanism was removed in commit 75cc28648574
("configure: remove backwards-compatibility code", 2023-01-11) because
the fixups were obsolete at the time; however, the Meson deprecation
mechanism doesn't quite work when options are finally removed, so we
need to bring it back.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/configure b/configure
index bcab685cfd97..f7cd376e525f 100755
--- a/configure
+++ b/configure
@@ -1987,6 +1987,14 @@ if test "$skip_meson" = no; then
   if test "$?" -ne 0 ; then
       error_exit "meson setup failed"
   fi
+else
+  if test -f meson-private/cmd_line.txt; then
+    # Adjust old command line options that were removed
+    # sed -i is not portable
+    perl -i -ne '
+      /^sphinx_build/ && next;
+      print;' meson-private/cmd_line.txt
+  fi
 fi
 
 # Save the configure command line for later reuse.
-- 
2.40.1