Protect the system headers.

This commit was SVN r17252.

opal/mca/carto/auto_detect/carto_auto_detect_module.c

@@ -24,10 +24,18 @@
    guaranteed to have <unistd.h> and friends */
 #include <stdio.h>
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif  /* HAVE_UNISTD_H */
+#ifdef HAVE_STDLIB_H
 #include <stdlib.h>
+#endif  /* HAVE_STDLIB_H */
+#ifdef HAVE_STRING_H
 #include <string.h>
+#endif  /* HAVE_STRING_H */
+#ifdef HAVE_ERRNO_H
 #include <errno.h>
+#endif  /* HAVE_ERRNO_H */
 
 #include "opal/constants.h"
 #include "opal/mca/base/mca_base_param.h"

opal/mca/carto/file/carto_file_module.c

@@ -24,10 +24,18 @@
    guaranteed to have <unistd.h> and friends */
 #include <stdio.h>
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif  /* HAVE_UNISTD_H */
+#ifdef HAVE_STDLIB_H
 #include <stdlib.h>
+#endif  /* HAVE_STDLIB_H */
+#ifdef HAVE_STRING_H
 #include <string.h>
+#endif  /* HAVE_STRING_H */
+#ifdef HAVE_ERRNO_H
 #include <errno.h>
+#endif  /* HAVE_ERRNO_H */
 
 #include "opal/constants.h"
 #include "opal/mca/base/mca_base_param.h"