Offline build from julia-1.8.4-full.tar.gz failes dues to missing source for ittapi

[NickCao]

To reproduce:

• offline build julia 1.8.4 from source with julia-1.8.4-full.tar.gz
• failing with the following log when configuring llvm

CMake Error at lib/ExecutionEngine/IntelJITEvents/CMakeLists.txt:20 (message):
git clone https://github.com/intel/ittapi.git failed with No such file or
directory, please clone https://github.com/intel/ittapi.git

Workaround:
Add LLVM_CMAKE=-DITTAPI_SOURCE_DIR=<local checkout of ittapi> to make flags

[inkydragon]

This is a performance test tool and it could be ignored.
Workaround: echo 'USE_INTEL_JITEVENTS = 0' > Make.user

The Instrumentation and Tracing Technology (ITT) API enables your application to generate and control the collection of trace data during its execution across different Intel tools.

---

Next, add intel/ittapi as a conditional dependency of LLVM, if USE_INTEL_JITEVENTS is set.
Or do not use IntelJITEvents by default.

Currently, we use IntelJITEvents by default on linux.

julia/Make.inc

Lines 437 to 444 in 00177eb

	# Set to 1 to enable profiling with perf
	ifeq ("$(OS)", "Linux")
	USE_PERF_JITEVENTS ?= 1
	USE_INTEL_JITEVENTS ?= 1
	else
	USE_PERF_JITEVENTS ?= 0
	USE_INTEL_JITEVENTS ?= 0
	endif

git blame: #47586, @vchuravy

[nalimilan]

Bump @vchuravy. It's not great that by default the build needs to download sources from the Internet. This means that if the URL changes in the future Julia builds won't be reproducible.

[vchuravy]

The problem is that the source tarball we use is a snapshot of the git one. So this is not "our" choice.

@staticfloat and @giordano have been talking about source tarballs for JLLs which would fix this particular problem.

The other option is that we try to do some trickery during the building of our source tarball.

[nalimilan]

Sounds tricky. Could we include a tarball in the source and pass LLVM_CMAKE=-DITTAPI_SOURCE_DIR=<local checkout of ittapi> as proposed in the OP?

[vchuravy]

That could work. I wanted to add an option to build with ittapi for better profiling of the Julia runtime anyways.

Could you investigate this?