sim: common: clean up asprintf includes a bit

Delete stale prototypes that libiberty.h already provides, and add
missing libiberty.h includes to files that use those functions.

sim/common/ChangeLog

@@ -1,3 +1,8 @@
+2021-01-09  Mike Frysinger  <vapier@gentoo.org>
+
+	* sim-basics.h [__CYGWIN32__] (vasprintf, asprintf): Delete.
+	* sim-core.c, sim-watch.c: Include libiberty.h.
+
 2021-01-09  Mike Frysinger  <vapier@gentoo.org>
 
 	* acinclude.m4: Replace duplicate text with pointer to README-HACKING.

sim/common/sim-basics.h

@@ -37,11 +37,6 @@
 #include <stdio.h>
 #include <setjmp.h>
 
-#ifdef __CYGWIN32__
-extern int vasprintf (char **result, const char *format, va_list args);
-extern int asprintf (char **result, const char *format, ...);
-#endif
-
 
 #ifndef NULL
 #define NULL 0

sim/common/sim-core.c

@@ -25,6 +25,7 @@
 
 #include "sim-main.h"
 #include "sim-assert.h"
+#include "libiberty.h"
 
 #if (WITH_HW)
 #include "sim-hw.h"

sim/common/sim-watch.c

@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "config.h"
 #include "sim-main.h"
 #include "sim-options.h"
+#include "libiberty.h"
 
 #include "sim-assert.h"