Autoconf 2.72 seems to be under preparation upstream, I therefore started to build dependent components to verify that they can be built once it lands in Fedora.

Your component fails to build with the new version of autoconf, due to the following error:

---
checking for cc_r... gcc
./configure: line 5993: syntax error near unexpected token `;;'
./configure: line 5993: `printf "%s\n" "$as_me: WARNING: --with-system-editline specified, not found. Using bundled editline" >&2;} ;;'
error: Bad exit status from /var/tmp/rpm-tmp.yKcOUe (%build)
RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.yKcOUe (%build)
Child return code was: 1
---

The error is due to a misplace 'fi' in configure.ac.

The proposed patch is the following:

---
diff -r -U5 Firebird-4.0.2.2816-0/configure.ac Firebird-4.0.2.2816-0.new/configure.ac
--- Firebird-4.0.2.2816-0/configure.ac	2022-11-22 12:03:35.566718554 +0100
+++ Firebird-4.0.2.2816-0.new/configure.ac	2022-11-22 12:03:28.606705774 +0100
@@ -652,12 +652,13 @@
   AC_CHECK_LIB(edit, readline, [READLINE=edit EDITLINE_FLG=Y],
     AC_CHECK_LIB(editline, readline, [READLINE=editline EDITLINE_FLG=Y],
       AC_CHECK_LIB(readline, readline, [READLINE=readline EDITLINE_FLG=Y],
         [STD_EDITLINE=false
          if test "$EDITLINE_FLG" = "Y"; then
-           AC_MSG_WARN([[[--with-system-editline specified, not found. Using bundled editline]]])])))
+           AC_MSG_WARN([[[--with-system-editline specified, not found. Using bundled editline]]])
 		 fi
+           ])))
 fi
 XE_RESTORE_ENV()
 
 AC_SUBST(READLINE)
 AC_SUBST(STD_EDITLINE)
---

Please have a look and get it fixed upstream.