[Patch v3 09/11] CryptoPkg IntrinsicLib: Make _fltused always be used

["Liming Gao" <liming.gao@intel.com>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1603
With this change, global variable _fltused will not be removed by LTO

Signed-off-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
---
 CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c b/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c
index 6e4d4a68cc..94fe341bec 100644
--- a/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c
+++ b/CryptoPkg/Library/IntrinsicLib/MemoryIntrinsics.c
@@ -2,7 +2,7 @@
   Intrinsic Memory Routines Wrapper Implementation for OpenSSL-based
   Cryptographic Library.
 
-Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -13,9 +13,15 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 typedef UINTN  size_t;
 
+#if defined(__GNUC__) || defined(__clang__)
+  #define GLOBAL_USED __attribute__((used))
+#else
+  #define GLOBAL_USED
+#endif
+
 /* OpenSSL will use floating point support, and C compiler produces the _fltused
    symbol by default. Simply define this symbol here to satisfy the linker. */
-int _fltused = 1;
+int  GLOBAL_USED _fltused = 1;
 
 /* Sets buffers to a specified character */
 void * memset (void *dest, int ch, size_t count)
-- 
2.13.0.windows.1