Just take what is currently in core as gospel

Author: John Peacock

vutil/vutil.h

@@ -255,4 +255,32 @@ const char * Perl_prescan_version(pTHX_ const char *s, bool strict, const char**
 #define UNLOCK_NUMERIC_STANDARD()
 #endif
 
+#ifndef LOCK_LC_NUMERIC_STANDARD
+/* Lock/unlock to the C locale until unlock is called.  This needs to be
+ * recursively callable.  [perl #128207] */
+#  define LOCK_LC_NUMERIC_STANDARD()                                        \
+        STMT_START {                                                        \
+            DEBUG_Lv(PerlIO_printf(Perl_debug_log,                          \
+                      "%s: %d: lock lc_numeric_standard: new depth=%d\n",   \
+                      __FILE__, __LINE__, PL_numeric_standard + 1));        \
+            __ASSERT_(PL_numeric_standard)                                  \
+            PL_numeric_standard++;                                          \
+        } STMT_END
+#endif
+
+#ifndef UNLOCK_LC_NUMERIC_STANDARD
+#  define UNLOCK_LC_NUMERIC_STANDARD()                                      \
+        STMT_START {                                                        \
+            if (PL_numeric_standard > 1) {                                  \
+                PL_numeric_standard--;                                      \
+            }                                                               \
+            else {                                                          \
+                assert(0);                                                  \
+            }                                                               \
+            DEBUG_Lv(PerlIO_printf(Perl_debug_log,                          \
+            "%s: %d: lc_numeric_standard decrement lock, new depth=%d\n",   \
+            __FILE__, __LINE__, PL_numeric_standard));                      \
+        } STMT_END
+#endif
+
 /* ex: set ro: */