add execlp

sources/nix20/extra/execlp.c

@@ -0,0 +1,25 @@
+#include <stdarg.h>
+#include <unistd.h>
+
+int execlp(const char * file, const char *arg, ...) {
+	va_list v;
+
+	// count
+	va_start(v, arg);
+	int argc = 1;
+	while (va_arg(v, const char *)) {
+		++argc;
+	}
+	va_end(v);
+
+	const char * argv[argc + 1];
+	argv[0] = arg;
+
+	va_start(v, arg);
+	for (int i = 1; i < argc; ++i) {
+		argv[i] = va_arg(v, const char *);
+	}
+	va_end(v);
+
+	return execvp(file, argv);
+}