Fix compiler warnings about not used dummy() functions

It has been reported that the Microsoft Visual C compiler complains if
a .c file do not contain any compilable code, which can happen if the
code has been #ifdef'ed out.  To avoid this, these #ifdef sections have
a #else section which adds a static dummy() function which does nothing.

On the other hand, the GNU C compiler complains about unused functions when
it discovers this situation.

This patch tries to only add these dummy() functions if the Microsoft Visual C
compiler is detected, via the _MSC_VER macro.

Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>
Acked-by: Peter Stuge <peter@stuge.se>

cryptoapi.c

@@ -470,5 +470,7 @@ int SSL_CTX_use_CryptoAPI_certificate(SSL_CTX *ssl_ctx, const char *cert_prop)
 }
 
 #else
+#ifdef _MSC_VER  /* Dummy function needed to avoid empty file compiler warning in Microsoft VC */
 static void dummy (void) {}
+#endif
 #endif				/* WIN32 */

ieproxy.c

@@ -139,7 +139,8 @@ LPCTSTR getIeHttpProxy()
     return(NULL);
   }
 }
-
 #else
+#ifdef _MSC_VER  /* Dummy function needed to avoid empty file compiler warning in Microsoft VC */
 static void dummy (void) {}
+#endif
 #endif				/* WIN32 */

perf.c

@@ -287,5 +287,7 @@ perf_print_state (int lev)
 }
 
 #else
+#ifdef _MSC_VER  /* Dummy function needed to avoid empty file compiler warning in Microsoft VC */
 static void dummy(void) {}
 #endif
+#endif

pkcs11.c

@@ -982,5 +982,7 @@ cleanup:
 }
 
 #else
+#ifdef _MSC_VER  /* Dummy function needed to avoid empty file compiler warning in Microsoft VC */
 static void dummy (void) {}
+#endif
 #endif /* ENABLE_PKCS11 */