Fix gssapi headers on OpenBSD (#125546)

Without the additional `include_directories` the compiler won't find
`#include <gssapi/gssapi.h>`.

Contributes to #124911.

Author: sethjackson

src/native/libs/configure.cmake

@@ -22,9 +22,8 @@ elseif (CLR_CMAKE_TARGET_FREEBSD)
     include_directories(SYSTEM ${CROSS_ROOTFS}/usr/local/include)
     set(CMAKE_REQUIRED_INCLUDES ${CROSS_ROOTFS}/usr/local/include)
 elseif (CLR_CMAKE_TARGET_OPENBSD)
-    include_directories(SYSTEM ${CROSS_ROOTFS}/usr/local/include)
-    set(CMAKE_REQUIRED_INCLUDES ${CROSS_ROOTFS}/usr/local/include)
-    set(CMAKE_REQUIRED_INCLUDES ${CROSS_ROOTFS}/heimdal/include)
+    include_directories(SYSTEM ${CROSS_ROOTFS}/usr/local/include ${CROSS_ROOTFS}/heimdal/include)
+    set(CMAKE_REQUIRED_INCLUDES ${CROSS_ROOTFS}/usr/local/include ${CROSS_ROOTFS}/heimdal/include)
 elseif (CLR_CMAKE_TARGET_SUNOS)
     # requires /opt/tools when building in Global Zone (GZ)
     include_directories(SYSTEM /opt/local/include /opt/tools/include)