perf-test.cc file is missing __STDC_WANT_LIB_EXT1__ option to have str???_s
functions defined.

This is a Solaris specific patch.

--- a/test/perf-test.cc	2020-10-01 21:44:58.000000000 +0200
+++ b/test/perf-test.cc	2020-11-10 09:23:38.566053281 +0100
@@ -18,6 +18,9 @@
      of a previous run.
 */
 
+// str*_s() functions needs this to be defined.
+#define __STDC_WANT_LIB_EXT1__ 1
+
 #ifdef _MSC_VER
 // this sucks but I don't know any other way
 #    pragma comment(linker, "/manifestdependency:\"type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='x86' publicKeyToken='6595b64144ccf1df' language='*'\"")