Fix wrong conditions
diff --git a/contrib/premake/zstd.lua b/contrib/premake/zstd.lua
index 0f7fc55..df1ace3 100644
--- a/contrib/premake/zstd.lua
+++ b/contrib/premake/zstd.lua
@@ -9,12 +9,12 @@
 
 	if legacy == nil then legacy = 0 end
 
-	if compression then
+	if not compression then
 		dictbuilder = false
 		deprecated = false
 	end
 
-	if decompression then
+	if not decompression then
 		legacy = 0
 		deprecated = false
 	end