cgo: add FreeRTOS compatibility headers

This is especially useful if we ever want to support the ESP-IDF.

Author: aykevl

compileopts/config.go

@@ -201,6 +201,9 @@ func (c *Config) RP2040BootPatch() bool {
 // preprocessing.
 func (c *Config) CFlags() []string {
 	var cflags []string
+	// Compatibility CFlags.
+	cflags = append(cflags, "-I"+filepath.Join(goenv.Get("TINYGOROOT"), "src/compat/freertos/include"))
+	// CFlags for the target.
 	for _, flag := range c.Target.CFlags {
 		cflags = append(cflags, strings.ReplaceAll(flag, "{root}", goenv.Get("TINYGOROOT")))
 	}

src/compat/freertos/include/freertos/FreeRTOS.h

@@ -0,0 +1,5 @@
+#include <stdint.h>
+
+typedef uint32_t     TickType_t;
+typedef int          BaseType_t;
+typedef unsigned int UBaseType_t;

src/compat/freertos/include/freertos/queue.h

@@ -0,0 +1 @@
+typedef struct QueueDefinition * QueueHandle_t;