Added exit() function and renamed stdlib file to libc.a so GCC is happy.

targets/_any/stdlib/SConscript

@@ -28,7 +28,7 @@ if env['BUILD_TARGET'] == 'stdlib':
     stdlib_env.Append(CPPPATH = ['#targets/_any/bastl/include', '#targets/_any/stdlib/include', '#targets/_any/kernel/include'])
 
     lib_stdlib = stdlib_env.StaticLibrary(
-        target = stdlib_env.File('#stdlib/stdlib.a'),
+        target = stdlib_env.File('#stdlib/libc.a'),
         source = stdlib_sources
     )
     crti_o = stdlib_env.Object(target = '#stdlib/crti.o', source = stdlib_env['CRTI_PATH'])

targets/_any/stdlib/src/stdlib.cpp

@@ -3,6 +3,7 @@
 
 #include <stddef.h>
 #include "os/memory.hpp"
+#include "os/syscall.hpp"
 #include "os/tty.hpp"
 
 namespace
@@ -44,6 +45,15 @@ void abort()
     __builtin_unreachable();
 }
 
+void exit(int exitCode) noexcept
+{
+#if !defined(__baos_kernel_source__)
+    baos::doSyscall(baos::Syscall::EXIT, exitCode);
+#else
+    abort(); // no exit in kernel!
+#endif
+}
+
 void* malloc(size_t size) noexcept
 {
     if (size == 0)