Drop libgcc and default to libc++ for NetBSD/ARM on 6.99.40+.
Don't bother with keeping the old support for x86_64 in 6.99.23+, just
use a single range. Update test cases for the always-on --eh-frame-hdr.

llvm-svn: 208170
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 99d15f72..b86df2a 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -6608,8 +6608,12 @@
   unsigned Major, Minor, Micro;
   getToolChain().getTriple().getOSVersion(Major, Minor, Micro);
   bool useLibgcc = true;
-  if (Major >= 7 || (Major == 6 && Minor == 99 && Micro >= 23) || Major == 0) {
+  if (Major >= 7 || (Major == 6 && Minor == 99 && Micro >= 40) || Major == 0) {
     switch(getToolChain().getArch()) {
+    case llvm::Triple::arm:
+    case llvm::Triple::armeb:
+    case llvm::Triple::thumb:
+    case llvm::Triple::thumbeb:
     case llvm::Triple::x86:
     case llvm::Triple::x86_64:
       useLibgcc = false;