Add information gathered through getauxval()

Suggested by Wladimir van der Laan.

src/randomenv.cpp

@@ -57,6 +57,9 @@
 #include <sys/vmmeter.h>
 #endif
 #endif
+#ifdef __linux__
+#include <sys/auxv.h>
+#endif
 
 //! Necessary on some platforms
 extern char** environ;
@@ -329,6 +332,28 @@ void RandAddStaticEnv(CSHA512& hasher)
     // Bitcoin client version
     hasher << CLIENT_VERSION;
 
+#ifdef __linux__
+    // Information available through getauxval()
+#  ifdef AT_HWCAP
+    hasher << getauxval(AT_HWCAP);
+#  endif
+#  ifdef AT_HWCAP2
+    hasher << getauxval(AT_HWCAP2);
+#  endif
+#  ifdef AT_RANDOM
+    const unsigned char* random_aux = (const unsigned char*)getauxval(AT_RANDOM);
+    if (random_aux) hasher.Write(random_aux, 16);
+#  endif
+#  ifdef AT_PLATFORM
+    const char* platform_str = (const char*)getauxval(AT_PLATFORM);
+    if (platform_str) hasher.Write((const unsigned char*)platform_str, strlen(platform_str) + 1);
+#  endif
+#  ifdef AT_EXECFN
+    const char* exec_str = (const char*)getauxval(AT_EXECFN);
+    if (exec_str) hasher.Write((const unsigned char*)exec_str, strlen(exec_str) + 1);
+#  endif
+#endif // __linux__
+
 #ifdef HAVE_GETCPUID
     AddAllCPUID(hasher);
 #endif