[C++][Release] Linux nightly verification jobs failing with Could NOT find LLVMAlt

[amoeba]

Describe the bug, including details regarding any error messages, version, and platform.

A cluster of Linux nightly verification jobs are failing to find LLVM using our FindLLVMAlt.cmake:

-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find LLVM (missing: LLVM_DIR)
CMake Error at /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find LLVMAlt (missing: LLVM_PACKAGE_VERSION CLANG_EXECUTABLE
  LLVM_FOUND LLVM_LINK_EXECUTABLE)
Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  cmake_modules/FindLLVMAlt.cmake:125 (find_package_handle_standard_args)
  src/gandiva/CMakeLists.txt:30 (find_package)

(Excepted from https://github.com/ursacomputing/crossbow/actions/runs/12619675362/job/35164487847)

We'll need to resolve this before the 19.0.0 release.

Component(s)

C++, Release

[amoeba]

I tracked this down to a recent change in our setup-ubuntu script made in 2533a9e#diff-0e63916abbe6f2640d5b3713c14b62c952ce93d6bbb4b0d7b17d65ab8e44cead as part of GH-45047 which effectively removed llvm-dev from our images.

(The --no-install-recommends version of the clang package doesn't install llvm-dev which provides the necessary LLVMConfig.cmake.)

@kou @raulcd @assignUser: I think we can just add llvm-dev to the main list in setup-ubuntu (so it's always present). What do you think? I've tested locally.

[kou]

Oh, sorry. I missed it.
Yes. We should install llvm-dev.

[kou]

Issue resolved by pull request 45184
#45184