Build with LTO

Resolves: rhbz#2188418

llvm.spec

@@ -79,7 +79,7 @@ ver:rc%{rc_ver}}.src
 
 Name:		%{pkg_name}
 Version:	%{maj_ver}.%{min_ver}.%{patch_ver}%{?rc_ver:~rc%{rc_ver}}
-Release:	1%{?dist}
+Release:	2%{?dist}
 Summary:	The Low Level Virtual Machine
 
 License:	Apache-2.0 WITH LLVM-exception OR NCSA
@@ -270,12 +270,10 @@ mv %{third_party_srcdir} third-party
 
 %build
 
-#ifarch s390 s390x
-# Fails with "exceeded PCRE's backtracking limit"
+%ifarch %ix86
+# Linking libLLVM.so goes out of memory even with ThinLTO and a single link job.
 %global _lto_cflags %nil
-#else
-#global _lto_cflags -flto=thin
-#endif
+%endif
 
 %ifarch s390 s390x %{arm} %ix86
 # Decrease debuginfo verbosity to reduce memory consumption during final library linking
@@ -645,6 +643,9 @@ fi
 %endif
 
 %changelog
+* Fri May 05 2023 Nikita Popov <npopov@redhat.com> - 16.0.1-2
+- Build with LTO
+
 * Fri Apr 14 2023 Nikita Popov <npopov@redhat.com> - 16.0.1-1
 - Update to LLVM 16.0.1