Hardening in case a thread's frames are missing.

<rdar://problem/13254824>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175806 91177308-0d34-0410-b5e6-96231b3b80d8
Mark test as expected-to-fail with GCC because some versions emit DWARF that claims
functions start at the line with the "{" character, whereas clang uses the first line
with source code. As such, this test case will only work with clang.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175808 91177308-0d34-0410-b5e6-96231b3b80d8
git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175810 91177308-0d34-0410-b5e6-96231b3b80d8
Previous commit was bogus (testing)

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175811 91177308-0d34-0410-b5e6-96231b3b80d8
Update INSTALL.txt to mention LLDB builds on Linux with GCC or Clang.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@175816 91177308-0d34-0410-b5e6-96231b3b80d8