Add program api to tinyrt

include/cia_definitions.h

@@ -3,6 +3,7 @@
 
 // Pre-C23 keyword macros and stddef
 #define static_assert _Static_assert
+#define noreturn _Noreturn
 #define NULL ((void *)0)
 
 // Platform macros

src/linux/syscall.c

@@ -167,8 +167,9 @@ static inline i64 syscall_close(u32 fd) {
     return __syscall1(SYS_close, fd);
 }
 
-static inline i64 syscall_exit(int code) {
-    return __syscall1(SYS_exit, (i64)code);
+static inline noreturn void syscall_exit(int code) {
+    __syscall1(SYS_exit, (i64)code);
+    __builtin_unreachable();
 }
 
 static inline i64 syscall_arch_prctl_set(int code, u64 value) {

src/linux/tinyrt.c

@@ -55,3 +55,7 @@ static RT_Status rt_file_close(RT_File *file) {
     }
     return RT_STATUS_OK;
 }
+
+static noreturn void rt_program_exit(int code) {
+    syscall_exit(code);
+}

src/linux/tinyrt.mf

@@ -11,3 +11,5 @@
 #     #define RT_API_FILE
 
 file = 1
+program = 1
+shell = 0

src/tinyrt.h

@@ -41,6 +41,16 @@ static bool _rt_api_tmpfile;
 static RT_Status rt_init();
 static RT_Status rt_deinit();
 
+// Program API
+#if RT_API_PROGRAM == 1
+    static noreturn void rt_program_exit(int code);
+#endif
+
+#if RT_API_ENVIRONMENT == 1
+    static RT_Status rt_shell_exec(char const *cmd);
+    static RT_Status rt_env_get(char const *name);
+#endif
+
 // File API
 #if RT_API_FILE == 1
     struct RT_File typedef RT_File;