fix a crash in arg handling on Windows

we were not updating argc in vips.c after all calls to
g_option_context_parse_strv() on Windows, leading to a crash in some cases

see https://github.com/jcupitt/libvips/issues/553

ChangeLog

@@ -1,3 +1,6 @@
+11/11/16 started 8.4.4
+- fix crash in vips.exe arg parsing on Windows, thanks Yury
+
 18/10/16 started 8.4.3
 - fix error detection in gif_close, thanks aaron42net
 - fix tiny threading memleak

configure.ac

@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT([vips], [8.4.3], [vipsip@jiscmail.ac.uk])
+AC_INIT([vips], [8.4.4], [vipsip@jiscmail.ac.uk])
 # required for gobject-introspection
 AC_PREREQ(2.62)
 
@@ -18,7 +18,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [8])
 m4_define([vips_minor_version], [4])
-m4_define([vips_micro_version], [3])
+m4_define([vips_micro_version], [4])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -38,7 +38,7 @@ VIPS_VERSION_STRING=$VIPS_VERSION-`date`
 #   binary interface changes not backwards compatible?: reset age to 0
 
 LIBRARY_CURRENT=48
-LIBRARY_REVISION=3
+LIBRARY_REVISION=4
 LIBRARY_AGE=6
 
 # patched into include/vips/version.h

tools/vips.c

@@ -1041,12 +1041,18 @@ parse_options( GOptionContext *context, int *argc, char **argv )
 		vips_error_exit( NULL );
 	}
 
+	/* On Windows, argc will not have been updated by
+	 * g_option_context_parse_strv().
+	 */
+	for( *argc = 0; argv[*argc]; (*argc)++ )
+		;
+
 	/* Remove any "--" argument. If one of our arguments is a negative
 	 * number, the user will need to have added the "--" flag to stop
 	 * GOption parsing. But "--" is still passed down to us and we need to
 	 * ignore it.
 	 */
-	for( i = 1; i < *argc - 1; i++ )
+	for( i = 1; i < *argc; i++ )
 		if( strcmp( argv[i], "--" ) == 0 ) {
 			for( j = i; j < *argc; j++ )
 				argv[j] = argv[j + 1];