Expose the std_detect env_override feature

Author: lu-zero

library/std/Cargo.toml

@@ -72,6 +72,7 @@ panic_immediate_abort = ["core/panic_immediate_abort"]
 # https://github.com/rust-lang/stdarch/blob/master/crates/std_detect/Cargo.toml
 std_detect_file_io = ["std_detect/std_detect_file_io"]
 std_detect_dlsym_getauxval = ["std_detect/std_detect_dlsym_getauxval"]
+std_detect_env_override = ["std_detect/std_detect_env_override"]
 
 [package.metadata.fortanix-sgx]
 # Maximum possible number of threads when testing

library/test/Cargo.toml

@@ -33,3 +33,4 @@ panic_immediate_abort = ["std/panic_immediate_abort"]
 profiler = ["std/profiler"]
 std_detect_file_io = ["std/std_detect_file_io"]
 std_detect_dlsym_getauxval = ["std/std_detect_dlsym_getauxval"]
+std_detect_env_override = ["std/std_detect_env_override"]