[ATfE] rename VERSION.TXT in overlay packages (arm#507)

[ATfE] rename VERSION.txt in overlay packages

The file currently has the same name in an overlay package as it does in
the base toolchain that the overlay is installed on top of, so when
unpacking the overlay package, the two files collide and the base
toolchain's version is overwritten.

Author: vrukesh

arm-software/embedded/CMakeLists.txt

@@ -569,12 +569,20 @@ add_custom_target(
     -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/generate_version_txt.cmake
     BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/VERSION.txt
 )
-install(
-    FILES
-    ${CMAKE_CURRENT_BINARY_DIR}/VERSION.txt
-    DESTINATION .
-    COMPONENT llvm-toolchain-third-party-licenses
-)
+if(NOT (LLVM_TOOLCHAIN_C_LIBRARY STREQUAL picolibc))
+    install(
+        FILES "${CMAKE_CURRENT_BINARY_DIR}/VERSION.txt"
+        DESTINATION .
+        RENAME VERSION_${LLVM_TOOLCHAIN_C_LIBRARY}.txt
+        COMPONENT llvm-toolchain-third-party-licenses
+    )
+else()
+    install(
+        FILES "${CMAKE_CURRENT_BINARY_DIR}/VERSION.txt"
+        DESTINATION .
+        COMPONENT llvm-toolchain-third-party-licenses
+    )
+endif()
 
 
 # Groups all the targets that comprise the toolchain.