diff --git a/evconfig-private.h.cmake b/evconfig-private.h.cmake
index 32f04794..1adf9c03 100644
--- a/evconfig-private.h.cmake
+++ b/evconfig-private.h.cmake
@@ -32,4 +32,9 @@
 /* Define to 1 if you need to in order for `stat' and other things to work. */
 #cmakedefine _POSIX_SOURCE 1
 
+/* Enable POSIX.2 extensions on QNX for getopt */
+#ifdef __QNX__
+#cmakedefine __EXT_POSIX2 1
+#endif
+
 #endif
diff --git a/evconfig-private.h.in b/evconfig-private.h.in
index 7b3dfdb1..8cd64787 100644
--- a/evconfig-private.h.in
+++ b/evconfig-private.h.in
@@ -45,4 +45,11 @@
 #undef _POSIX_SOURCE
 #endif
 
+/* Enable POSIX.2 extensions on QNX for getopt */
+#ifdef __QNX__
+# ifndef __EXT_POSIX2
+#  define __EXT_POSIX2
+# endif
+#endif
+
 #endif