diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index 1b8d28a695..328292e699 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -103,7 +103,31 @@ check_struct_has_member("struct tm"       tm_zone        time.h       HAVE_STRUC
 #Symbols but NOT enums or types
 check_symbol_exists(tzname "time.h" HAVE_TZNAME)
 
-# Check for stuff that isn't testable via the tests above
+#
+# Check if the libc vsnprintf() conforms to C99. If this fails we may
+# need to fall-back on GLib I/O.
+#
+check_c_source_runs("
+	#include <stdio.h>
+	int main(void)
+	{
+		/* Check that snprintf() and vsnprintf() don't return
+		 * -1 if the buffer is too small. C99 says this value
+		 * is the length that would be written not including
+		 * the nul byte. */
+		char buf[3];
+		return snprintf(buf, sizeof(buf), \"%s\", \"ABCDEF\") > 0 ? 0 : 1;
+	}"
+	HAVE_C99_VSNPRINTF
+)
+if (NOT HAVE_C99_VSNPRINTF)
+	message(FATAL_ERROR
+"Building Wireshark requires a C99 compliant vsnprintf() and this \
+target does not meet that requirement. Compiling for ${CMAKE_SYSTEM} \
+using ${CMAKE_C_COMPILER_ID}. Please report this issue to the Wireshark \
+developers at wireshark-dev@wireshark.org."
+	)
+endif()
 
 #
 # *If* we found libnl, check if we can use nl80211 stuff with it.