adding xxhash

.gitmodules

@@ -4,6 +4,6 @@
 [submodule "Juliet/external/stb"]
 	path = Juliet/external/stb
 	url = https://github.com/nothings/stb.git
-[submodule "Juliet/external/xxhash"]
+[submodule "Juliet/external/xxHash"]
-	path = Juliet/external/xxhash
+	path = Juliet/external/xxHash
 	url = https://github.com/Cyan4973/xxHash.git

Juliet/core/core_hash.c

@@ -1,11 +1,21 @@
 // =============================================================================
 // Hash Functions
 
-#define HASH_STRING 4259
+#pragma push_macro("__cpuid")
+#undef __cpuid
+#if !defined(XXH_IMPLEMENTATION)
+# define XXH_INLINE_ALL
+# define XXH_IMPLEMENTATION
+# define XXH_STATIC_LINKING_ONLY
+# include "external/xxHash/xxhash.h"
+#endif
+#pragma pop_macro("__cpuid")
+
+#define HASH_SEED 4259
 
 internal uint64 uint64_hash_from_string(String8 string)
 {
-    uint64 result = uint64_hash_from_seed_string(HASH_STRING, string);
+    uint64 result = uint64_hash_from_seed_string(HASH_SEED, string);
     return result;
 }