Try to remove -lunwind from link flags

The possible reason why tests fail is that
MAYBE there are another libunwind on the testing host
which is loaded(?) instead of libunwind from llvm.
clang passes 'right' libunwind (-lunwind) to the linker
if -unwindlib=libunwind is passed to the driver

Author: chestnykh

libunwind/test/configs/llvm-libunwind-shared.cfg.in

@@ -23,6 +23,10 @@ if '@CMAKE_DL_LIBS@':
 # Stack unwinding tests need unwinding tables and these are not generated by default on all targets.
 compile_flags.append('-funwind-tables')
 
+# Use libunwind from llvm
+compile_flags.append('-rtlib=compiler-rt')
+compile_flags.append('-unwindlib=libunwind')
+
 local_sysroot = '@CMAKE_OSX_SYSROOT@' or '@CMAKE_SYSROOT@'
 config.substitutions.append(('%{flags}',
     '-isysroot {}'.format(local_sysroot) if local_sysroot else ''
@@ -31,7 +35,7 @@ config.substitutions.append(('%{compile_flags}',
     '-nostdinc++ -I %{{include}} {}'.format(' '.join(compile_flags))
 ))
 config.substitutions.append(('%{link_flags}',
-    '-L %{{lib}} -Wl,-rpath,%{{lib}} -lunwind {}'.format(' '.join(link_flags))
+    '-L %{{lib}} -Wl,-rpath,%{{lib}} {}'.format(' '.join(link_flags))
 ))
 config.substitutions.append(('%{exec}',
     '%{executor} --execdir %T -- '