Safety checks: Indirect through a function.

This will let us share code on failure pathways.pathways

src/safety_check.c

@@ -0,0 +1,11 @@
+#include "jemalloc/internal/jemalloc_preamble.h"
+#include "jemalloc/internal/jemalloc_internal_includes.h"
+
+void safety_check_fail(const char *format, ...) {
+	va_list ap;
+
+	va_start(ap, format);
+	malloc_vcprintf(NULL, NULL, format, ap);
+	va_end(ap);
+	abort();
+}