Driver: only inject libstdc++ paths when needed on CrossWindows

When building with libc++ don't bother with injecting the libstdc++
search paths into the linker search path.  This will make it easier to
switch between ld and lld.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302184 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Driver/ToolChains/CrossWindows.cpp

@@ -204,7 +204,7 @@ CrossWindowsToolChain::CrossWindowsToolChain(const Driver &D,
                                              const llvm::Triple &T,
                                              const llvm::opt::ArgList &Args)
     : Generic_GCC(D, T, Args) {
-  if (GetCXXStdlibType(Args) == ToolChain::CST_Libstdcxx) {
+  if (D.CCCIsCXX() && GetCXXStdlibType(Args) == ToolChain::CST_Libstdcxx) {
     const std::string &SysRoot = D.SysRoot;
 
     // libstdc++ resides in /usr/lib, but depends on libgcc which is placed in

test/Driver/windows-cross.c

-// RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -stdlib=libstdc++ -rtlib=platform -o /dev/null %s 2>&1 \
-// RUN:   | FileCheck %s --check-prefix CHECK-BASIC
+// RUN: %clang -### --driver-mode=g++ -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -stdlib=libstdc++ -rtlib=platform -o /dev/null %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-BASIC-LIBSTDCXX
 
-// CHECK-BASIC: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/gcc" "{{.*}}.o" "-lmsvcrt" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
+// CHECK-BASIC-LIBSTDCXX: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/gcc" "{{.*}}.o" "-lstdc++" "-lmingw32" "-lmingwex" "-lgcc" "-lmoldname" "-lmingw32" "-lmsvcrt" "-lgcc_s" "-lgcc"
+
+// RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -stdlib=libstdc++ -rtlib=compiler-rt -o /dev/null %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK-BASIC-LIBCXX
+
+// CHECK-BASIC-LIBCXX: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{[^"]*}}.o" "-lmsvcrt"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %s/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -rtlib=compiler-rt -stdlib=libstdc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-RTLIB
 
-// CHECK-RTLIB: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/gcc" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-RTLIB: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -rtlib=compiler-rt -stdlib=libc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-C-LIBCXX