Fix llvm_process_sources to append source file properties instead of overriding it

[joker-eph]

This fixes the CLANG_VENDOR macro that disappeared because it is set using the same mechanism and one was overriding the other.

[joker-eph]

@nathanchance if you want to confirm this fixes the issue?

[nathanchance]

@joker-eph Thanks, this appears to resolve my issue.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder mlir-nvidia running on mlir-nvidia while building llvm at step 7 "test-build-check-mlir-build-only-check-mlir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/138/builds/16804

Here is the relevant piece of the build log for the reference

Step 7 (test-build-check-mlir-build-only-check-mlir) failure: test (failure)
******************** TEST 'MLIR :: Integration/GPU/CUDA/async.mlir' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -pass-pipeline='builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary="format=fatbin"  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so    --entry-point-result=void -O0  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt '-pass-pipeline=builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary=format=fatbin
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so --entry-point-result=void -O0
# .---command stderr------------
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventSynchronize(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# `-----------------------------
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# .---command stderr------------
# | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir:68:12: error: CHECK: expected string not found in input
# |  // CHECK: [84, 84]
# |            ^
# | <stdin>:1:1: note: scanning from here
# | Unranked Memref base@ = 0x5c596c2021f0 rank = 1 offset = 0 sizes = [2] strides = [1] data = 
# | ^
# | <stdin>:2:1: note: possible intended match here
# | [42, 42]
# | ^
# | 
# | Input file: <stdin>
# | Check file: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: Unranked Memref base@ = 0x5c596c2021f0 rank = 1 offset = 0 sizes = [2] strides = [1] data =  
# | check:68'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# |             2: [42, 42] 
# | check:68'0     ~~~~~~~~~
# | check:68'1     ?         possible intended match
...