[Clang] Pass -fseparate-named-sections from the driver (#91567)

This is a follow up to #91028.

Author: petrhosek

clang/lib/Driver/ToolChains/Clang.cpp

@@ -6146,6 +6146,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   Args.addOptOutFlag(CmdArgs, options::OPT_funique_section_names,
                      options::OPT_fno_unique_section_names);
+  Args.addOptInFlag(CmdArgs, options::OPT_fseparate_named_sections,
+                    options::OPT_fno_separate_named_sections);
   Args.addOptInFlag(CmdArgs, options::OPT_funique_internal_linkage_names,
                     options::OPT_fno_unique_internal_linkage_names);
   Args.addOptInFlag(CmdArgs, options::OPT_funique_basic_block_section_names,

clang/test/Driver/fseparate-named-sections.c

@@ -0,0 +1,4 @@
+// RUN: %clang -### -fseparate-named-sections %s -c 2>&1 | FileCheck -check-prefix=CHECK-OPT %s
+// RUN: %clang -### -fseparate-named-sections -fno-separate-named-sections %s -c 2>&1 | FileCheck -check-prefix=CHECK-NOOPT %s
+// CHECK-OPT: "-fseparate-named-sections"
+// CHECK-NOOPT-NOT: "-fseparate-named-sections"