curl: Check for OpenSSL headers independently

Use check_include_file instead of check_include_file_concat to look
for OpenSSL headers.  They do not need to participate in a sequence
of dependent system headers.  Also they may cause winsock.h to be
included before ws2tcpip.h, causing the latter to not be detected
in the sequence.

Utilities/cmcurl/CMakeLists.txt

@@ -443,15 +443,15 @@ if(CMAKE_USE_OPENSSL)
     set(HAVE_LIBSSL ON)
     include_directories(${OPENSSL_INCLUDE_DIR})
     set(CMAKE_REQUIRED_INCLUDES ${OPENSSL_INCLUDE_DIR})
-    check_include_file_concat("openssl/crypto.h" HAVE_OPENSSL_CRYPTO_H)
-    check_include_file_concat("openssl/engine.h" HAVE_OPENSSL_ENGINE_H)
-    check_include_file_concat("openssl/err.h"    HAVE_OPENSSL_ERR_H)
-    check_include_file_concat("openssl/pem.h"    HAVE_OPENSSL_PEM_H)
-    check_include_file_concat("openssl/pkcs12.h" HAVE_OPENSSL_PKCS12_H)
-    check_include_file_concat("openssl/rsa.h"    HAVE_OPENSSL_RSA_H)
-    check_include_file_concat("openssl/ssl.h"    HAVE_OPENSSL_SSL_H)
-    check_include_file_concat("openssl/x509.h"   HAVE_OPENSSL_X509_H)
-    check_include_file_concat("openssl/rand.h"   HAVE_OPENSSL_RAND_H)
+    check_include_file("openssl/crypto.h" HAVE_OPENSSL_CRYPTO_H)
+    check_include_file("openssl/engine.h" HAVE_OPENSSL_ENGINE_H)
+    check_include_file("openssl/err.h"    HAVE_OPENSSL_ERR_H)
+    check_include_file("openssl/pem.h"    HAVE_OPENSSL_PEM_H)
+    check_include_file("openssl/pkcs12.h" HAVE_OPENSSL_PKCS12_H)
+    check_include_file("openssl/rsa.h"    HAVE_OPENSSL_RSA_H)
+    check_include_file("openssl/ssl.h"    HAVE_OPENSSL_SSL_H)
+    check_include_file("openssl/x509.h"   HAVE_OPENSSL_X509_H)
+    check_include_file("openssl/rand.h"   HAVE_OPENSSL_RAND_H)
 
     # Optionally build with a specific CA cert bundle.
     set(CURL_CA_BUNDLE "" CACHE FILEPATH "Path to SSL CA Certificate Bundle")