fix abort_test for limited Windows regex. Refs mesonbuild/wrapdb#1611

PiperOrigin-RevId: 662785270

hwy/abort_test.cc

@@ -4,6 +4,8 @@
 
 #include "hwy/abort.h"
 
+#include <stdio.h>
+
 #include <string>
 
 #include "hwy/base.h"
@@ -27,14 +29,17 @@ TEST(AbortDeathTest, AbortDefault) {
 }
 
 TEST(AbortDeathTest, AbortOverride) {
+  // googletest regex does not support `+` for digits on Windows?!
+  // https://google.github.io/googletest/advanced.html#regular-expression-syntax
+  // We assume the line number is exactly 2 digits.
   std::string expected =
-      std::string("Test Abort from [0-9]+ of ") + GetBaseName(__FILE__);
+      std::string("Test Abort from \\d\\d of ") + GetBaseName(__FILE__);
 
   ASSERT_DEATH(
       {
         AbortFunc CustomAbortHandler = [](const char* file, int line,
                                           const char* formatted_err) -> void {
-          fprintf(stderr, "%s from %d of %s", formatted_err, line,
+          fprintf(stderr, "%s from %02d of %s", formatted_err, line,
                   GetBaseName(file).data());
         };
 
@@ -43,7 +48,7 @@ TEST(AbortDeathTest, AbortOverride) {
       },
       expected);
 }
-#endif
+#endif  // GTEST_HAS_DEATH_TEST
 
 TEST(AbortTest, AbortOverrideChain) {
   AbortFunc FirstHandler = [](const char* file, int line,