make: avo_alloca.h works around a very old Solaris bug, delete it

@@ -32,11 +32,11 @@
 
 /*
  * Included files
  */
 #include <sys/wait.h>                   /* WIFEXITED(status) */
-#include <avo/avo_alloca.h>             /* alloca() */
+#include <alloca.h>             /* alloca() */
 
 #if defined(TEAMWARE_MAKE_CMN) || defined(MAKETOOL) /* tolik */
 #       include <avo/strings.h> /* AVO_STRDUP() */
 #if defined(DISTRIBUTED)
 #       include <dm/Avo_CmdOutput.h>