Revert "Enable `-funwind-tables` flag when building libunwind"

This reverts commit b3fdf33ba6aa7ef80621696f74aaf2f6f8e1d1de.

This change broke building libunwind for Windows/MinGW, and broke
on aspect of the CMake tests in libunwind in general.

After set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY), CMake
skips the linking step in tests, but cmake/config-ix.cmake also
does a few checks for functions in libraries (looking for whether
-lc provides fopen and whether -ldl provides dladdr).

As CMake only tests building a static library, these tests
incorrectly succeed and CMake concludes "Looking for fopen in c -
found" and "Looking for dladdr in dl - found", while building
then fails at the end with errors about unable to find -lc and -ldl.

GitOrigin-RevId: 938c70b86c7d2165f8c28d5700e9c1ac1263307e
6 files changed