Remove explicit LLVM ccache-ing

[dyung]

Summary

I want to use ccache with icecream to distribute builds to a spare machine on my network, but explicitly building with -DLLVM_CCACHE_BUILD=ON doesn't work with it. I found that if I disabled that I can put the ccache version of the compiler on the path which gets used and then instruct ccache to use icecc to build allowing me to use both.

[gkistanova]

Interesting.
Could you tell me how ccache with icecream will work for you with a real load after a few weeks of working, please?

The patch looks good.

buildbot/osuosl/master/config/builders.py

'factory': UnifiedTreeBuilder.getCmakeWithNinjaBuildFactory(
                     depends_on_projects=['llvm','clang','lldb','cross-project-tests'],
                     checks = ['check-cross-project'],
                     extra_configure_args=[
                         "-DCMAKE_C_COMPILER=gcc",
                         "-DCMAKE_CXX_COMPILER=g++",
                         "-DCMAKE_BUILD_TYPE=Release",
                         "-DCLANG_ENABLE_ARCMT=OFF",
                         "-DLLDB_ENABLE_PYTHON=TRUE",
-                        "-DLLVM_CCACHE_BUILD=ON",
                         "-DLLVM_INCLUDE_EXAMPLES=OFF",
                         "-DLLVM_ENABLE_ASSERTIONS=ON",
                         "-DLLVM_LIT_ARGS=--verbose",
                         "-DLLVM_TARGETS_TO_BUILD=X86",
                         "-DLLVM_USE_LINKER=gold"])},
 
     {'name': "cross-project-tests-sie-ubuntu-dwarf5",
     'tags'  : ["clang", "llvm", "lldb", "cross-project-tests"],
     'workernames': ["doug-worker-1b"],
     'builddir': "cross-project-tests-sie-ubuntu-dwarf5",
     'factory': UnifiedTreeBuilder.getCmakeWithNinjaBuildFactory(
                     depends_on_projects=['llvm','clang','lldb','cross-project-tests'],
                     checks = ['check-cross-project'],
                     extra_configure_args=[
                         "-DCMAKE_C_COMPILER=gcc",
                         "-DCMAKE_CXX_COMPILER=g++",
                         "-DCMAKE_BUILD_TYPE=Release",
                         "-DCLANG_ENABLE_ARCMT=OFF",
                         "-DLLDB_ENABLE_PYTHON=TRUE",
-                        "-DLLVM_CCACHE_BUILD=ON",
                         "-DLLVM_INCLUDE_EXAMPLES=OFF",
                         "-DLLVM_ENABLE_ASSERTIONS=ON",
                         "-DLLVM_LIT_ARGS=--verbose",
                         "-DLLVM_TARGETS_TO_BUILD=X86",
                         "-DLLVM_USE_LINKER=gold"])},
 
     {'name': "llvm-clang-x86_64-gcc-ubuntu",
     'tags'  : ["llvm", "clang", "clang-tools-extra", "compiler-rt", "lld", "cross-project-tests"],
     'workernames': ["doug-worker-2a"],
     'builddir': "llvm-clang-x86_64-gcc-ubuntu",
     'factory': UnifiedTreeBuilder.getCmakeWithNinjaBuildFactory(
                     depends_on_projects=['llvm','clang','clang-tools-extra','compiler-rt','lld','cross-project-tests'],
                     extra_configure_args=[
                         "-DCMAKE_C_COMPILER=gcc",
                         "-DCMAKE_CXX_COMPILER=g++",
                         "-DCMAKE_BUILD_TYPE=Release",
                         "-DCLANG_ENABLE_CLANGD=OFF",
                         "-DLLVM_BUILD_RUNTIME=ON",
                         "-DLLVM_BUILD_TESTS=ON",
-                        "-DLLVM_CCACHE_BUILD=ON",
                         "-DLLVM_ENABLE_ASSERTIONS=ON",
                         "-DLLVM_INCLUDE_EXAMPLES=OFF",
                         "-DLLVM_LIT_ARGS=--verbose -j48",
                         "-DLLVM_USE_LINKER=gold"])},
 
 # Polly builders.
 
     {'name' : "polly-arm-linux",