Tested with //GCC 1.30 Tool#2 patchlevel 5// and //GCC 2.6.3 Lv.3 Exp.20//.

Build with either:
<file>gcc hello.c -ldos -o hello.x</file>
<file>gcc2 hello.c -ldos -o hello.x</file>

Code:
<file>
#include <doslib.h>

void main(int argc, char *argv[])
{
        _PRINT("Hello world!\n");
}
</file>