VmgExitLib fails to build with the CLANG38 toolset (clang 13.0.0):


edk2/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c:1875:9: error: 
variable 'Compacted' is used uninitialized whenever 'if' condition is 
false [-Werror,-W
sometimes-uninitialized]
    if (EcxIn == 1) {
        ^~~~~~~~~~
edk2/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c:1895:12: note: 
uninitialized use occurs here
           Compacted
           ^~~~~~~~~
edk2/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c:1875:5: note: remove 
the 'if' if its condition is always true
    if (EcxIn == 1) {
    ^~~~~~~~~~~~~~~~
edk2/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c:1871:37: note: 
initialize the variable 'Compacted' to silence this warning
    BOOLEAN                Compacted;
                                    ^
                                     = '\0'

-- 
Rebecca Cran