removed all std dependencies … WIP move to embassy pure rust code

rust/build.rs

@@ -1,6 +1,54 @@
 use std::process::Command;
 
 use vergen::EmitBuilder;
+
+fn linker_be_nice() {
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() > 1 {
+        let kind = &args[1];
+        let what = &args[2];
+
+        match kind.as_str() {
+            "undefined-symbol" => match what.as_str() {
+                "_defmt_timestamp" => {
+                    eprintln!();
+                    eprintln!("💡 `defmt` not found - make sure `defmt.x` is added as a linker script and you have included `use defmt_rtt as _;`");
+                    eprintln!();
+                }
+                "_stack_start" => {
+                    eprintln!();
+                    eprintln!("💡 Is the linker script `linkall.x` missing?");
+                    eprintln!();
+                }
+                "esp_wifi_preempt_enable"
+                | "esp_wifi_preempt_yield_task"
+                | "esp_wifi_preempt_task_create" => {
+                    eprintln!();
+                    eprintln!("💡 `esp-wifi` has no scheduler enabled. Make sure you have the `builtin-scheduler` feature enabled, or that you provide an external scheduler.");
+                    eprintln!();
+                }
+                "embedded_test_linker_file_not_added_to_rustflags" => {
+                    eprintln!();
+                    eprintln!("💡 `embedded-test` not found - make sure `embedded-test.x` is added as a linker script for tests");
+                    eprintln!();
+                }
+                _ => (),
+            },
+            // we don't have anything helpful for "missing-lib" yet
+            _ => {
+                std::process::exit(1);
+            }
+        }
+
+        std::process::exit(0);
+    }
+
+    println!(
+        "cargo:rustc-link-arg=--error-handling-script={}",
+        std::env::current_exe().unwrap().display()
+    );
+}
+
 fn main() {
     println!("cargo:rerun-if-changed=./src/src_webpack");
     Command::new("rm")
@@ -64,7 +112,6 @@ fn main() {
                 .unwrap();
         }
     }
-
-    embuild::espidf::sysenv::output();
+    linker_be_nice();
     let _ = EmitBuilder::builder().all_git().all_build().emit();
 }