Clean up, add some documentation, and make this test return to checking
the linker toolchainness a bit more thoroughly. It used to work this
way, but hit buildbot issues. Hopefully subsequent fixes have addressed
those problems, but I'll be watching the bots.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151090 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/gcc-toolchain.cpp b/test/Driver/gcc-toolchain.cpp
index f56b110..5529a5d 100644
--- a/test/Driver/gcc-toolchain.cpp
+++ b/test/Driver/gcc-toolchain.cpp
@@ -4,22 +4,20 @@
 // RUN:     -target i386-unknown-linux \
 // RUN:     -gcc-toolchain %S/Inputs/ubuntu_11.04_multiarch_tree/usr \
 // RUN:   | FileCheck %s
-
+//
+// Test for header search toolchain detection.
 // CHECK: "-internal-isystem"
 // CHECK: "[[TOOLCHAIN:[^"]+]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/../../../../../include/c++/4.5"
 // CHECK: "-internal-isystem"
 // CHECK: "[[TOOLCHAIN]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/../../../../../include/c++/4.5/i686-linux-gnu"
 // CHECK: "-internal-isystem"
 // CHECK: "[[TOOLCHAIN]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/../../../../../include/c++/4.5/backward"
-// CHECK: "-internal-isystem"
-// CHECK: "/usr/local/include"
-// CHECK: "-internal-isystem"
-// CHECK: lib/clang/3.1/include"
-// CHECK: "-internal-externc-isystem"
-// CHECK: "/include"
-// CHECK: "-internal-externc-isystem"
-// CHECK: "/usr/include"
+// CHECK: "-internal-isystem" "/usr/local/include"
+//
+// Test for linker toolchain detection. Note that we use a separate variable
+// because the '/'s may be different in the linker invocation than in the
+// header search.
 // CHECK: "{{[^"]*}}ld{{(.exe)?}}"
-// CHECK: "{{[^"]*}}/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/crtbegin.o"
-// CHECK: "-L{{[^"]*}}/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5"
-// CHECK: "-L{{[^"]*}}/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/../../../.."
+// CHECK: "[[TOOLCHAIN2:[^"]*]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/crtbegin.o"
+// CHECK: "-L[[TOOLCHAIN2]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5"
+// CHECK: "-L[[TOOLCHAIN2]]/usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.5/../../../.."