TCBZ2596: Added FltUsedLib to MdePkg

added FltUsedLib, submitted a feature request to TianoCore

MdePkg/Library/FltUsedLib/FltUsedLib.c

@@ -0,0 +1,10 @@
+/** @file
+  Lib to include if using floats
+
+Copyright (C) Microsoft Corporation.
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+// You need to include this to let the compiler know we are going to use floating point
+int  _fltused = 0x9875;

MdePkg/Library/FltUsedLib/FltUsedLib.inf

@@ -0,0 +1,31 @@
+## @file
+#  Lib to include if using floats
+#
+# Copyright (C) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = FltUsedLib
+  FILE_GUID                      = C004F180-9FE2-4D2B-8318-BADC2A231774
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = FltUsedLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
+#
+
+[Sources]
+  FltUsedLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[BuildOptions]
+  # Disable GL due to linker error LNK1237
+  # https://docs.microsoft.com/en-us/cpp/error-messages/tool-errors/linker-tools-error-lnk1237?view=vs-2017
+  MSFT:*_*_*_CC_FLAGS = /GL-

MdePkg/Library/FltUsedLib/Readme.md

@@ -0,0 +1,15 @@
+# FltUsedLib
+
+This library provides a global (fltused) that needs to be defined anywhere floating point operations are used.
+The C compiler produces the _fltused symbol by default, this is just to satisfy the linker.
+
+## Using
+
+To use FltUsedLib, just include it in the INF of the module that uses floating point.
+
+```inf
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  FltUsedLib
+```

MdePkg/MdePkg.ci.yaml

@@ -119,6 +119,7 @@
     "DscCompleteCheck": {
         "IgnoreInf": [
             "MdePkg/Library/VsIntrinsicLib/VsIntrinsicLib.inf",   # MU_CHANGE - Ignore intrinsics for toolchains that don't support it.
+            "MdePkg/Library/FltUsedLib/FltUsedLib.inf" # MU_CHANGE this isn't compilable since it has no code
         ],
         "DscPath": "MdePkg.dsc"
     },