* Check for <unistd.h>, too. MSVC doesn't have it.

configure.ac

@@ -27,7 +27,7 @@ esac
 AC_SUBST(WINSOCK2_LIBS)
 AC_SUBST(DLL_LDFLAGS)
 
-AC_CHECK_HEADERS(windows.h winsock2.h io.h inttypes.h stdint.h getopt.h libc.h malloc.h dlfcn.h regex.h sys/socket.h sys/uio.h aio.h sys/mman.h sys/wait.h sys/resource.h sys/time.h)
+AC_CHECK_HEADERS(windows.h winsock2.h io.h unistd.h inttypes.h stdint.h getopt.h libc.h malloc.h dlfcn.h regex.h sys/socket.h sys/uio.h aio.h sys/mman.h sys/wait.h sys/resource.h sys/time.h)
 
 AC_CHECK_FUNCS(setenv waitpid setrlimit gettimeofday fork kill pipe _pipe)
 AC_CHECK_FUNCS(open64 lseek64 mmap64 fopen64 fseeko _IO_getc getline getdelim __getdelim fgetln __srefill map_fd memalign posix_memalign aio_read accept socket readv pread recv recvfrom recvmsg mmap valloc sigaction)

src/debug.c

@@ -27,7 +27,9 @@
 #   include <inttypes.h>
 #endif
 #include <stdio.h>
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #include <errno.h>
 #include <stdarg.h>
 

src/lib-fd.c

@@ -45,7 +45,9 @@
 #if defined HAVE_SYS_UIO_H
 #   include <sys/uio.h>
 #endif
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #include <fcntl.h>
 #include <stdarg.h>
 #if defined HAVE_AIO_H

src/lib-mem.c

@@ -40,7 +40,9 @@
 #if defined HAVE_MALLOC_H
 #   include <malloc.h>
 #endif
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #if defined HAVE_SYS_MMAN_H
 #   include <sys/mman.h>
 #endif

src/lib-stream.c

@@ -29,7 +29,7 @@
 
 #include <stdio.h>
 #include <sys/types.h>
-#if defined HAVE___SREFILL
+#if defined HAVE___SREFILL && defined HAVE_UNISTD_H
 #   include <unistd.h> /* Needed for __srefill’s lseek() call */
 #endif
 

src/libzzuf.c

@@ -29,7 +29,9 @@
 #endif
 #include <stdio.h>
 #include <sys/types.h>
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #include <stdlib.h>
 #include <string.h>
 #include <fcntl.h>

src/zzuf.c

@@ -28,7 +28,9 @@
 #endif
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #if defined HAVE_REGEX_H
 #   include <regex.h>
 #endif

test/zzcat.c

@@ -19,7 +19,9 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-#include <unistd.h>
+#if defined HAVE_UNISTD_H
+#   include <unistd.h>
+#endif
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>