Fix stringifying static array of unsigned chars

The fix leaves an open question: should we keep treating refs
to static array of chars as strings, or should we instead
use `strnlen` to check if it is null-terminated within the buffer

Fixes #1238

projects/SelfTest/UsageTests/Compilation.tests.cpp

@@ -7,6 +7,8 @@
 
 #include "catch.hpp"
 
+#include <cstring>
+
 namespace { namespace CompilationTests {
 
 #ifndef COMPILATION_TEST_HELPERS_INCLUDED // Don't compile this more than once per TU
@@ -134,4 +136,15 @@ namespace { namespace CompilationTests {
         REQUIRE(t1 >= t2);
     }
 
+    // unsigned array
+    TEST_CASE("#1238") {
+        unsigned char uarr[] = "123";
+        CAPTURE(uarr);
+        signed char sarr[] = "456";
+        CAPTURE(sarr);
+
+        REQUIRE(std::memcmp(uarr, "123", sizeof(uarr)) == 0);
+        REQUIRE(std::memcmp(sarr, "456", sizeof(sarr)) == 0);
+    }
+
 }} // namespace CompilationTests