CryptoPkg/openssl: move compiler_flags to buildinf.c

Seems with openssl 3.0 this is used by multiple source files,
so we get duplicate symbol errors when linking.  Fix that by
moving compiler_flags from header file to a source file.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Xiaoyu Lu <xiaoyu1.lu@intel.com>
Cc: Guomin Jiang <guomin.jiang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Brian J. Johnson <brian.johnson@hpe.com>
Tested-by: Kenneth Lautner <klautner@microsoft.com>

CryptoPkg/Library/OpensslLib/buildinf.c

@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: BSD-2-Clause-Patent */
+#include "buildinf.h"
+
+const char  *compiler_flags = "compiler: information not available from edk2";