Some pre-POSIX systems don't have unistd.h (but e.g. lib.c).

Allow configuring the name of that header file.

crypto/bf/bf_opts.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern void exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/bf/bfspeed.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/cast/cast_spd.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/cast/castopts.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern void exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/des/des.c

@@ -60,7 +60,8 @@
 #include <stdlib.h>
 #ifndef MSDOS
 #ifndef VMS
-#include <unistd.h>
+#include <openssl/opensslconf.h>
+#include OPENSSL_UNISTD
 #else /* VMS */
 #ifdef __DECC
 #include <unistd.h>

crypto/des/des_locl.h

@@ -67,15 +67,16 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+
+#include <openssl/opensslconf.h>
+
 #ifndef MSDOS
 #if !defined(VMS) || defined(__DECC)
-#include <unistd.h>
+#include OPENSSL_UNISTD
 #endif
 #endif
 #include <openssl/des.h>
 
-#include <openssl/opensslconf.h>
-
 #ifdef MSDOS		/* Visual C++ 2.1 (Windows NT/95) */
 #include <stdlib.h>
 #include <errno.h>

crypto/des/des_opts.c

@@ -65,7 +65,8 @@
 
 #include <stdio.h>
 #ifndef MSDOS
-#include <unistd.h>
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD
 #else
 #include <io.h>
 extern void exit();

crypto/des/destest.c

@@ -66,7 +66,8 @@
 #include <stdlib.h>
 #ifndef MSDOS
 #if !defined(VMS) || defined(__DECC)
-#include <unistd.h>
+#include <openssl/opensslconf.h>
+#include OPENSSL_UNISTD
 #endif /* VMS */
 #else
 #include <io.h>

crypto/des/read_pwd.c

@@ -57,7 +57,8 @@
  */
 
 #if !defined(MSDOS) && !defined(VMS) && !defined(WIN32)
-#include <unistd.h>
+#include <openssl/opensslconf.h>
+#include OPENSSL_UNISTD
 /* If unistd.h defines _POSIX_VERSION, we conclude that we
  * are on a POSIX system and have sigaction and termios. */
 #if defined(_POSIX_VERSION)

crypto/des/speed.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/idea/idea_spd.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/opensslconf.h.in

@@ -10,6 +10,8 @@
 #endif
 #endif
 
+#define OPENSSL_UNISTD <unistd.h>
+
 #if defined(HEADER_IDEA_H) && !defined(IDEA_INT)
 #define IDEA_INT unsigned int
 #endif

crypto/rc2/rc2speed.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/rc4/rc4speed.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

crypto/rc5/rc5speed.c

@@ -64,12 +64,11 @@
 #endif
 
 #include <stdio.h>
-#ifndef MSDOS
-#include <unistd.h>
-#else
-#include <io.h>
-extern int exit();
-#endif
+
+#include <openssl/e_os2.h>
+#include OPENSSL_UNISTD_IO
+OPENSSL_DECLARE_EXIT
+
 #include <signal.h>
 #ifndef _IRIX
 #include <time.h>

e_os2.h

@@ -7,6 +7,16 @@
 extern "C" {
 #endif
 
+#include <openssl/opensslconf.h> /* OPENSSL_UNISTD */
+
+#ifdef MSDOS
+# define OPENSSL_UNISTD_IO <io.h>
+# define OPENSSL_DECLARE_EXIT extern void exit(int);
+#else
+# define OPENSSL_UNISTD_IO OPENSSL_UNISTD
+# define OPENSSL_DECLARE_EXIT /* declared in unistd.h */
+#endif
+
 /* Definitions of OPENSSL_GLOBAL and OPENSSL_EXTERN,
    to define and declare certain global
    symbols that, with some compilers under VMS, have to be defined and