[cmake] Add cmake file for hexagon-builtins baremetal

[quic-k]

This will be used to build hexagon-builtins for baremetal.

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[quic-k]

@ldionne
tagging you as you approved a similar PR previously

[github-actions]

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[llvm-ci]

LLVM Buildbot has detected a new failure on builder clang-ppc64le-linux-test-suite running on ppc64le-clang-test-suite while building compiler-rt at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/95/builds/18264

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

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'SanitizerCommon-asan-powerpc64le-Linux :: Linux/getpwnam_r_invalid_user.cpp' FAILED ********************
Exit Code: 134

Command Output (stderr):
--
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/./bin/clang  --driver-mode=g++ -gline-tables-only -fsanitize=address  -m64 -fno-function-sections -funwind-tables  -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/compiler-rt/test -ldl -O0 -g /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/getpwnam_r_invalid_user.cpp -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.tmp &&  /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.tmp # RUN: at line 2
+ /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/./bin/clang --driver-mode=g++ -gline-tables-only -fsanitize=address -m64 -fno-function-sections -funwind-tables -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/compiler-rt/test -ldl -O0 -g /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/getpwnam_r_invalid_user.cpp -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.tmp
+ /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.tmp
getpwnam_r_invalid_user.cpp.tmp: /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/compiler-rt/test/sanitizer_common/TestCases/Linux/getpwnam_r_invalid_user.cpp:17: int main(): Assertion `res == 0 || res == ENOENT' failed.
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.script: line 1: 2529410 Aborted                 /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-powerpc64le-Linux/Linux/Output/getpwnam_r_invalid_user.cpp.tmp

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