Add FindRust cmake utility

cmake/FindRust.cmake

@@ -0,0 +1,28 @@
+# Try to find compatible Rust toolchain
+# Once done this will define
+#  RUST_FOUND - If a compatible toolchain was found
+#  RUST_CARGO_DIR - The path to the cargo executable
+#  RUST_CARGO - The path to the cargo executable
+#  RUST_VERSION - The toolchain version
+
+set(PATH_HINTS "$ENV{USERPROFILE}" "${HOME}")
+if(NOT RUST_CARGO_DIR)
+    set(RUST_CARGO_DIR "${USER_HOME}/.cargo")
+elseif()
+    message(STATUS "Using supplied rust cargo directory: ${RUST_CARGO_DIR}")
+endif()
+find_program(RUST_CARGO cargo HINTS ${RUST_CARGO_DIR} PATH_SUFFIXES "bin")
+
+set(RUST_FOUND FALSE CACHE INTERNAL "")
+
+if(RUST_CARGO)
+    set(RUST_FOUND TRUE CACHE INTERNAL "")
+    execute_process(COMMAND ${RUST_CARGO} --version OUTPUT_VARIABLE RUST_VERSION OUTPUT_STRIP_TRAILING_WHITESPACE)
+    string(REGEX REPLACE "cargo ([^ ]+) .*" "\\1" RUST_VERSION "${RUST_VERSION}")
+endif()
+
+if(NOT RUST_FOUND)
+    message(FATAL_ERROR "Could NOT find Rust toolchain. Please configure with -RUST_CARGO_DIR=<path to cargo directory> or set the RUST_CARGO_DIR environment variable.")
+endif()
+
+message(STATUS "Found Rust: ${RUST_CARGO_DIR} (${RUST_VERSION})")