build-llvm: Fix the selection of python import library

Since cpython-mingw v3.11 (see cpython-mingw commit
8aeb46d09c068a1228e83b29101c17bf1ff0612a), the versionless, stable
ABI libpython3.dll gets installed, along with libpython3.dll.a.

Ideally we would use this, which gets us better flexibility, but
in practice, LLDB fails to link against this, as it doesn't expose
enough of the symbols we use and need.

Previously, we ended up with PYTHON_LIB containing two path names,
which caused CMake to print warnings about ignoring extra paths
on the command line.

This fixes issue #396.

build-llvm.sh

@@ -204,7 +204,7 @@ if [ -n "$HOST" ]; then
         EXT_SUFFIX="$(echo $(bash $PREFIX/python/bin/python3-config --extension-suffix))"
         PYTHON_RELATIVE_PATH="$(cd "$PREFIX" && echo python/lib/python*/site-packages)"
         PYTHON_INCLUDE_DIR="$(echo $PREFIX/python/include/python*)"
-        PYTHON_LIB="$(echo $PREFIX/python/lib/libpython*.dll.a)"
+        PYTHON_LIB="$(echo $PREFIX/python/lib/libpython3.*.dll.a)"
         CMAKEFLAGS="$CMAKEFLAGS -DLLDB_ENABLE_PYTHON=ON"
         CMAKEFLAGS="$CMAKEFLAGS -DPYTHON_HOME=$PREFIX/python"
         CMAKEFLAGS="$CMAKEFLAGS -DLLDB_PYTHON_HOME=../python"