More patches from Jeff Law, plus a little cleanup of my own.

These changes separate PA-SOM support from PA-ELF support.
A sun4-x-hppaosf assembler can now be built.

Include <stdlib.h> and <unistd.h>.  Do not define malloc or free.

bfd/hosts/hppabsd.h

@@ -9,9 +9,8 @@
 #include <ctype.h>
 #include <string.h>
 #include <sys/file.h>
-
-extern PTR  malloc PARAMS ((unsigned));
-extern void free   PARAMS ((PTR));
+#include <stdlib.h>
+#include <unistd.h>
 
 #define HOST_HPPABSD