Fix glibc32 build dependency

Harmonize with Fedora and RHEL9 system gcc to make sure it always picks
the correct glibc32 from buildroot.

Also sync with the c10s spec file.

Resolves: RHEL-113182

gcc-toolset-15-gcc.spec

@@ -4,6 +4,7 @@
 %global have_scl_utils 0
 %endif
 %global gts_ver 15
+%global gts_next  %(v="%{gts_ver}"; echo $((++v)))
 %{?scl_package:%global scl gcc-toolset-%{gts_ver}}
 %global scl_prefix gcc-toolset-%{gts_ver}-
 %if %have_scl_utils
@@ -171,7 +172,7 @@ BuildRequires: gcc-toolset-%{gts_ver}-devel
 Summary: GCC version %{gcc_major}
 Name: %{?scl_prefix}gcc
 Version: %{gcc_version}
-Release: %{gcc_release}.4%{?dist}
+Release: %{gcc_release}.5%{?dist}
 # License notes for some of the less obvious ones:
 #   gcc/doc/cppinternals.texi: Linux-man-pages-copyleft-2-para
 #   isl: MIT, BSD-2-Clause
@@ -251,12 +252,10 @@ BuildRequires: libzstd-devel
 BuildRequires: glibc >= 2.3.90-35
 %endif
 %ifarch %{multilib_64_archs}
-# Ensure glibc{,-devel} is installed for both multilib arches
-%if 0%{?rhel} < 10
-BuildRequires: /lib/libc.so.6 /usr/lib/libc.so /lib64/libc.so.6 /usr/lib64/libc.so
-%else
-BuildRequires: /usr/lib/libc.so /usr/lib64/libc.so
+BuildRequires: (glibc32 or glibc-devel(%{__isa_name}-32))
 %endif
+%ifarch sparcv9 ppc
+BuildRequires: (glibc64 or glibc-devel(%{__isa_name}-64))
 %endif
 %ifarch ia64
 BuildRequires: libunwind >= 0.98
@@ -300,9 +299,7 @@ Requires: libgcc >= 4.1.2-43
 Requires: libgomp >= 4.4.4-13
 # lto-wrapper invokes make
 Requires: make
-%if %have_scl_utils
-%{?scl:Requires:%scl_runtime}
-%endif
+Requires: (%{?scl_prefix}runtime >= %{gts_ver} with %{?scl_prefix}runtime < %{gts_next})
 AutoReq: true
 # Various libraries are imported.  #1859893 asks us to list them all.
 Provides: bundled(libiberty)
@@ -826,13 +823,6 @@ sed -i '/^GENERATE_TREEVIEW/s/YES/NO/' libstdc++-v3/doc/doxygen/user.cfg.in
 # Undo the broken autoconf change in recent Fedora versions
 export CONFIG_SITE=NONE
 
-%if 0%{?rhel} == 10
-# Work around https://issues.redhat.com/browse/RHEL-49348
-%ifarch ppc64le
-export GLIBC_TUNABLES=glibc.cpu.hwcaps=-arch_3_1
-%endif
-%endif
-
 CC=gcc
 CXX=g++
 OPT_FLAGS="%{optflags}"
@@ -2912,6 +2902,9 @@ fi
 %endif
 
 %changelog
+* Tue Sep  9 2025 Siddhesh Poyarekar <siddhesh@redhat.com> 15.1.1-2.5
+- Fix glibc32 build dependency (RHEL-113182)
+
 * Mon Jun 16 2025 Marek Polacek <polacek@redhat.com> 15.1.1-2.4
 - ship libstdc++.modules.json (RHEL-97095)