configure.ac: Rework MESA_LLVM and LLVM detection

Set FOUND_LLVM only when LLVM is present (checking for exact version/etc
is deferred) and use enable-gallium-llvm to indicate the global LLVM
status.

Renaming the latter is not appropriate for stable patches, so we'll
address it with a later commit.

Loosely based on work by Tobias.

v2: Check FOUND_LLVM if enable_gallium_llvm is set.

Cc: Dave Airlie <[email protected]>
Cc: "17.0" <[email protected]>
Signed-off-by: Emil Velikov <[email protected]>
Reviewed-by: Tobias Droste <[email protected]>

0 files changed, 0 insertions, 0 deletions