Add support for 64bit atomics

src/ports/SkAtomics_sync.h

Index: src/ports/SkAtomics_sync.h
diff --git a/src/ports/SkAtomics_sync.h b/src/ports/SkAtomics_sync.h
index b0d17527f07f0c50271c09d9b6699423b72dd3fa..8135ae2e2ae28714bc6d133fa25c2c318231a86b 100644
--- a/src/ports/SkAtomics_sync.h
+++ b/src/ports/SkAtomics_sync.h
@@ -16,14 +16,26 @@ static inline __attribute__((always_inline)) int32_t sk_atomic_inc(int32_t* addr
     return __sync_fetch_and_add(addr, 1);
 }
 
+static inline __attribute__((always_inline)) int64_t sk_atomic_inc(int64_t* addr) {
+    return __sync_fetch_and_add(addr, 1);
+}
+
 static inline __attribute__((always_inline)) int32_t sk_atomic_add(int32_t* addr, int32_t inc) {
     return __sync_fetch_and_add(addr, inc);
 }
 
+static inline __attribute__((always_inline)) int64_t sk_atomic_add(int64_t* addr, int64_t inc) {
+    return __sync_fetch_and_add(addr, inc);
+}
+
 static inline __attribute__((always_inline)) int32_t sk_atomic_dec(int32_t* addr) {
     return __sync_fetch_and_add(addr, -1);
 }
 
+static inline __attribute__((always_inline)) int64_t sk_atomic_dec(int64_t* addr) {
+    return __sync_fetch_and_add(addr, -1);
+}
+
 static inline __attribute__((always_inline)) void sk_membar_acquire__after_atomic_dec() { }
 
 static inline __attribute__((always_inline)) bool sk_atomic_cas(int32_t* addr,
@@ -32,6 +44,12 @@ static inline __attribute__((always_inline)) bool sk_atomic_cas(int32_t* addr,
     return __sync_bool_compare_and_swap(addr, before, after);
 }
 
+static inline __attribute__((always_inline)) bool sk_atomic_cas(int64_t* addr,
+                                                                int64_t before,
+                                                                int64_t after) {
+    return __sync_bool_compare_and_swap(addr, before, after);
+}
+
 static inline __attribute__((always_inline)) void* sk_atomic_cas(void** addr,
                                                                  void* before,
                                                                  void* after) {