apps: use CMake check for getopt.h

Add CMake detection for getopt.h and update json_parse.c to include it
only when HAVE_GETOPT_H is defined. Fixes AIX build failure.

apps/CMakeLists.txt

@@ -94,6 +94,9 @@ endif() # end "standalone mode" block
 
 # ---------------------------------
 
+# Check whether getopt.h exists
+check_include_file(getopt.h HAVE_GETOPT_H)
+
 check_include_file(sys/resource.h   HAVE_SYS_RESOURCE_H) # for getrusage
 if (HAVE_SYS_RESOURCE_H)
     check_symbol_exists(getrusage   "sys/resource.h" HAVE_GETRUSAGE)

apps/json_parse.c

@@ -1,7 +1,9 @@
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
+#ifdef HAVE_GETOPT_H 
 #include <getopt.h>
+#endif
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>