diff --git a/public/crtlib.h b/public/crtlib.h
index 90bf1fce..94b77066 100644
--- a/public/crtlib.h
+++ b/public/crtlib.h
@@ -169,6 +169,16 @@ static inline char *Q_strstr( const char *s1, const char *s2 )
 }
 
 // libc extensions, be careful what to enable or what not
+static inline size_t Q_strnlen( const char *str, size_t size )
+{
+#if HAVE_STRNLEN
+	return strnlen( str, size );
+#else
+	const char *p = (const char *)memchr( str, 0, size );
+	return p ? p - str : size;
+#endif
+}
+
 static inline size_t Q_strncpy( char *dst, const char *src, size_t size )
 {
 	if( unlikely( !dst || !src || !size ))
diff --git a/public/wscript b/public/wscript
index ec87cb88..3a360212 100644
--- a/public/wscript
+++ b/public/wscript
@@ -29,6 +29,10 @@ int main(int argc, char **argv) { return strlcpy(argv[1], argv[2], 10); }'''
 STRLCAT_TEST = '''#include <string.h>
 int main(int argc, char **argv) { return strlcat(argv[1], argv[2], 10); }'''
 
+STRNLEN_TEST = '''#include <string.h>
+int main(int argc, char **argv) { return (int)strnlen(argv[0], 10); }
+'''
+
 ALLOCA_TEST = '''#include <%s>
 int main(void) { alloca(1); return 0; }'''
 
@@ -106,6 +110,7 @@ def configure(conf):
 		check_libc_extension(STRCHRNUL_TEST, 'strchrnul', 'HAVE_STRCHRNUL')
 		check_libc_extension(STRLCPY_TEST, 'strlcpy', 'HAVE_STRLCPY')
 		check_libc_extension(STRLCAT_TEST, 'strlcat', 'HAVE_STRLCAT')
+		check_libc_extension(STRNLEN_TEST, 'strnlen', 'HAVE_STRNLEN')
 
 	# kill temporary uselib
 	del conf.env.DEFINES_export