diff --git a/src/asm/main.c b/src/asm/main.c
index 5ba0c739..0cb94fa8 100644
--- a/src/asm/main.c
+++ b/src/asm/main.c
@@ -6,6 +6,7 @@
  */
 
 #include <math.h>
+#include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/fix/main.c b/src/fix/main.c
index ea7ca478..81c81bb9 100644
--- a/src/fix/main.c
+++ b/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>
diff --git a/src/link/main.c b/src/link/main.c
index a191ee9c..84ecb8f6 100644
--- a/src/link/main.c
+++ b/src/link/main.c
@@ -1,3 +1,4 @@
+#include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>