From: Tzafrir Cohen <tzafrir@debian.org>
Subject: Revert test for fallback of a test of broken std:regex
Forwarded: no

Some older versions of GCC (e.g. 4.8.5 in RHEL7 have a broken std::regex.
Currently this is detected by running generated code, and that breaks
cross-building.

On Debian we will have newer GCC anyway, so we don't care.

FIXME: Is there a test that does not require running code?

Index: mstflint/configure.ac
===================================================================
--- mstflint.orig/configure.ac	2024-01-24 13:58:40.452666711 +0200
+++ mstflint/configure.ac	2024-01-24 14:12:19.720655382 +0200
@@ -486,31 +486,8 @@
 AC_SUBST(LINUX_BUILD)
 AC_SUBST(LINUX_KERNEL_INCLUDE)
 
-# Certain older compilers may not fully support std::regex.
-# Signatuire is: the code compiles without issues, then it
-# crashes during runtime with:
-# terminate called after throwing an instance of 'std::regex_error'
-#  what():  regex_error
-# For those we resort to using GNU C regex as a fallback.
 AC_MSG_CHECKING([for std::regex compatibility])
-AC_LANG_PUSH([C++])
-AC_RUN_IFELSE([
-    AC_LANG_PROGRAM(
-        [[#include <regex>
-        ]],
-        [[std::regex e("[a-z]");]]
-    )
-],[
-    AC_MSG_RESULT([yes])
-],[
-    AC_MSG_RESULT([no])
-    AC_MSG_NOTICE([std::regex support appears to be incomplete; falling back to GNU C regex.])
-    AC_DEFINE([USE_STDLIB_REGEX], [1], [Whether to use GNU C regex])
-],[
-    AC_MSG_RESULT([yes])
-    AC_MSG_WARN([Assuming the cross-compiler has complete support for std::regex functionality. VERIFY BEFORE USING!!!])
-])
-AC_LANG_POP([C++])
+AC_MSG_RESULT([skipped])
 
 # we assume that project root may have a tools_git_sha
 TOOLS_GIT_SHA=$(cd $(dirname "$0"); ./eval_git_sha.sh)