libcompat: Add missing semicolon to vsnprintf() declaration

This makes the build fail on systems where vsnprintf() is missing or
not compliant enough, and thus the fallback is being used.

Closes: #612203

Signed-off-by: Guillem Jover <guillem@debian.org>

debian/changelog

@@ -32,6 +32,8 @@ dpkg (1.16.0) UNRELEASED; urgency=low
     now need --force-architecture, dpkg will still warn about them though.
   * Fix build failure when passing --disable-nls to configure.
   * Do not segfault on “dpkg -i --no-act”.
+  * Add missing semicolon to the vsnprintf() compat declaration.
+    Thanks to Robert Millan. Closes: #612203
 
   [ Raphaël Hertzog ]
   * Fail properly when debian/source/format is empty. Closes: #600854

lib/compat/compat.h

@@ -54,7 +54,7 @@ extern "C" {
 #include <stdarg.h>
 
 int snprintf(char *str, size_t n, char const *fmt, ...);
-int vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args)
+int vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args);
 #endif
 
 #ifndef HAVE_ASPRINTF