(S_IFLNK): Add #undef.

(C_SWITCH_SYSTEM): Add conditional definition.
(NO_ASM, USE_UTIME, NO_X_DESTROY_DATABASE): Defined.
(LIB_STANDARD): Alternate definition if __GNUC__.
(SIGTSTP): #undef deleted.
(LIBS_SYSTEM): Define only if HAVE_X_WINDOWS.

(USG_SHARED_LIBRARIES, CLASH_DETECTION, NO_FCHMOD): Define.
(HAVE_TIMEVAL): Do not define.
(NO_ASM): Only define once.

src/s/isc2-2.h

@@ -3,21 +3,67 @@
 
 #include "usg5-3.h"
 
+/* With this defined, subprocesses made by (e.g.) M-x grep don't exit
+   cleanly, they just hang.  ISC 2.2.1 does have select, in the -linet
+   library, but I guess it's not what Emacs needs.  --karl@cs.umb.edu
+#define HAVE_SELECT */
+
+/* Although ISC has sockets, again in -linet, again it's not what Emacs
+   needs.  With this defined, interrupt-shell-subjob and the like do
+   nothing.  --karl@cs.umb.edu
+#define HAVE_SOCKETS */
+
+
+/* This keeps the .cdbx section that gcc puts out when generating
+   stabs-in-coff output, so Emacs can be debugged.  --karl@cs.umb.edu*/
+#define USG_SHARED_LIBRARIES
+
+/* We can support lock files.  */
+#define CLASH_DETECTION
+#define NO_FCHMOD
+
 #define HAVE_PTYS
 #define HAVE_RENAME
 #define HAVE_CLOSEDIR
 #define MAXNAMLEN 512
-#define LIB_STANDARD -lPW -lcposix -lc
 #define O_NDELAY O_NONBLOCK
 #define MEMORY_IN_STRING_H
-#undef SIGTSTP
+
+/* -lcposix is always needed for rename.  -lPW is only needed if not gcc.  */
+#ifdef __GNUC__
+#define LIB_STANDARD -lcposix -lc
+#else
+#define LIB_STANDARD -lPW -lcposix -lc
+#endif
+
+/* mt00@etherm.co.uk says this is needed for process.c.  */
+#define USE_UTIME
+
+#define NO_X_DESTROY_DATABASE
 
 /* This communicates with m-intel386.h.  */
 #define DONT_DEFINE_SIGNAL
 
-/* May be needed to avoid undefined symbols
-   such as gethostname, inet_addr, gethostbyname, socket, connect... */
+/* May be needed to avoid undefined symbols such as gethostname,
+   inet_addr, gethostbyname, socket, connect, ...  But if we are not
+   compiling with X support, it's not needed.  */
+#ifdef HAVE_X_WINDOWS
 #define LIBS_SYSTEM -linet
+#endif
 
 /* This system has job control.  */
 #undef NOMULTIPLEJOBS
+
+/* Inhibit asm code in netinet/in.h.  Strictly speaking, only necessary
+   when -traditional is being used, but it doesn't hurt to
+   unconditionally define this.  */
+#define NO_ASM
+
+/* The POSIX-ified system headers don't work with GCC.  */
+#ifdef __GNUC__
+#define C_SWITCH_SYSTEM -traditional
+#endif
+
+/* Some versions of ISC are said to define S_IFLNK even tho
+   they don't really support symlinks.  */
+#undef S_IFLNK