Silence some GCC warnings.

This is from c89atomic which has been fixed upstream.

miniaudio.h

@@ -14878,14 +14878,18 @@ typedef int ma_atomic_memory_order;
         __atomic_compare_exchange_n(dst, &expected, desired, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
         return expected;
     }
-    #pragma clang diagnostic push
-    #pragma clang diagnostic ignored "-Watomic-alignment"
+    #if defined(__clang__)
+        #pragma clang diagnostic push
+        #pragma clang diagnostic ignored "-Watomic-alignment"
+    #endif
     static MA_INLINE ma_uint64 ma_atomic_compare_and_swap_64(volatile ma_uint64* dst, ma_uint64 expected, ma_uint64 desired)
     {
         __atomic_compare_exchange_n(dst, &expected, desired, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
         return expected;
     }
-    #pragma clang diagnostic pop
+    #if defined(__clang__)
+        #pragma clang diagnostic pop
+    #endif
     typedef ma_uint8 ma_atomic_flag;
     #define ma_atomic_flag_test_and_set_explicit(dst, order)        (ma_bool32)__atomic_test_and_set(dst, order)
     #define ma_atomic_flag_clear_explicit(dst, order)               __atomic_clear(dst, order)