use the same runtime_init() as for newlib -> picolibc now working for clang19.1.5/21.1.1

Author: rgrr

src/rp2_common/pico_clib_interface/picolibc_interface.c

@@ -124,9 +124,19 @@ void runtime_init(void) {
     runtime_init_per_core_install_stack_guard(&__StackBottom);
 #endif
 
-    // piolibc __libc_init_array does __preint_array and __init_array
-    extern void __libc_init_array(void);
-    __libc_init_array();
+    // todo maybe we want to do this in the future, but it does stuff like register_tm_clones
+    //      which we didn't do in previous SDKs
+    //extern void __libc_init_array(void);
+    //__libc_init_array();
+
+    // ... so instead just do the __preinit_array
+    runtime_run_initializers();
+    // ... and the __init_array
+    extern void (*__init_array_start)(void);
+    extern void (*__init_array_end)(void);
+    for (void (**p)(void) = &__init_array_start; p < &__init_array_end; ++p) {
+        (*p)();
+    }
 }
 
 #if !PICO_RUNTIME_NO_INIT_PER_CORE_TLS_SETUP
@@ -151,4 +161,4 @@ PICO_RUNTIME_INIT_FUNC_PER_CORE(runtime_init_pre_core_tls_setup, PICO_RUNTIME_IN
 //            "ldr r0, =__tls_base\n"
 //            "bx lr\n"
 //            );
-//}
+//}