[clang] [compiler-rt] [libcxx] [cmake] Add hexagon-linux cmake cache files (PR #98712)

[Louis Dionne via cfe-commits]

================
@@ -0,0 +1,25 @@
+
+set(LLVM_DEFAULT_TARGET_TRIPLE hexagon-unknown-linux-musl CACHE STRING "")
----------------
ldionne wrote:

Do you really need this setting here? Can't you instead set `CMAKE_CXX_COMPILER_TARGET`?

https://github.com/llvm/llvm-project/pull/98712