fixup PACKAGE_STRING macro

Mic92 · Mic92 · commit 10cd631cce92 · 2021-08-18T08:16:26.000+02:00
it was introduced in b9dcf5b but contained a stray \
diff --git a/src/patchelf.cc b/src/patchelf.cc
@@ -40,7 +40,7 @@
 
 #include "elf.h"
 
-#ifndef PACKAGE_STRING                          \
+#ifndef PACKAGE_STRING
 #define PACKAGE_STRING "patchelf"
 #endif
 
