Private library support improvement: search paths when loading an auxiliary
library.  This will make it easier to have clients that dynamically load
dbghelp.dll or other libraries on demand and keep their base states
simpler.  One use case is Windows early injection for Dr. Memory.

Add path searching to dr_load_aux_library():
+ Add locate_and_load_private_library() on Linux, and export
  on Windows
+ Switch load_shared_library() to use locate_and_load_private_library()

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1827 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
Add later-loaded priv libs to the windbg command buffer.  Previously they
were never added at all.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1828 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
Check return value of drsym_init() in drsym test so we can actually catch
errors there.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1829 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
fixes issue 1056

Handle CMAKE_CURRENT_LIST_DIR not being defined (it was added in CMake
2.8.3).  Also do not try to set the dynamic-scope cur-list-dir property
statically.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1830 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
fixes issue 967

Only call private library DllMain for DLL_THREAD_DETACH when exiting the
executing thread, not for exiting other threads.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1831 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6