build: fix Codacy/CppCheck warnings

- remove unused variables
- declare conditionally used variables conditionally
- suppress unused variable warnings in the CMake tests
- remove dead variable stores
- consistently use WIN32 macro to detect Windows

Closes https://github.com/curl/curl/pull/3739

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/md5.c b/lib/md5.c
index db4cc2656..e345065ea 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -124,7 +124,7 @@ static void MD5_Final(unsigned char digest[16], MD5_CTX *ctx)
   CC_MD5_Final(digest, ctx);
 }
 
-#elif defined(_WIN32) && !defined(CURL_WINDOWS_APP)
+#elif defined(WIN32) && !defined(CURL_WINDOWS_APP)
 
 #include <wincrypt.h>
 #include "curl_memory.h"