Include getopt.h (fix compilation on GNU/Linux)

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

src/asm/main.c

@@ -6,6 +6,7 @@
  */
 
 #include <math.h>
+#include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

src/fix/main.c

@@ -14,6 +14,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include <getopt.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>

src/link/main.c

@@ -1,3 +1,4 @@
+#include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>