CMake: add x86-64 feature levels

Add x86-64 feature levels from https://gitlab.com/x86-psABIs/x86-64-ABI
See also https://www.phoronix.com/scan.php?page=news_item&px=GCC-11-x86-64-Feature-Levels

Signed-off-by: Stephan Lachnit <stephanlachnit@debian.org>

cmake/OptimizeForArchitecture.cmake

@@ -230,7 +230,7 @@ Other supported values are: \"none\", \"generic\", \"core\", \"merom\" (65nm Cor
 \"haswell\", \"broadwell\", \"skylake\", \"skylake-xeon\", \"kaby-lake\", \"cannonlake\", \"icelake\", \"silvermont\", \
 \"goldmont\", \"knl\" (Knights Landing), \"atom\", \"k8\", \"k8-sse3\", \"barcelona\", \
 \"istanbul\", \"magny-cours\", \"bulldozer\", \"interlagos\", \"piledriver\", \
-\"AMD 14h\", \"AMD 16h\", \"zen\", \"zen3\".")
+\"AMD 14h\", \"AMD 16h\", \"zen\", \"zen3\", \"x86-64\", \"x86-64-v2\", \"x86-64-v3\", \"x86-64-v4\".")
    set(_force)
    if(NOT _last_target_arch STREQUAL "${TARGET_ARCHITECTURE}")
       message(STATUS "target changed from \"${_last_target_arch}\" to \"${TARGET_ARCHITECTURE}\"")
@@ -308,6 +308,25 @@ Other supported values are: \"none\", \"generic\", \"core\", \"merom\" (65nm Cor
       list(APPEND _march_flag_list "goldmont")
       _silvermont()
    endmacro()
+   macro(_x86_64)
+      list(APPEND _march_flag_list "x86-64")
+      list(APPEND _march_flag_list "sse" "sse2")
+   endmacro()
+   macro(_x86_64_v2)
+      list(APPEND _march_flag_list "x86-64-v2")
+      _x86_64()
+      list(APPEND _march_flag_list "sse3" "sse4.1" "sse4.2" "ssse3")
+   endmacro()
+   macro(_x86_64_v3)
+      list(APPEND _march_flag_list "x86-64-v3")
+      _x86_64_v2()
+      list(APPEND _march_flag_list "avx" "avx2" "bmi" "bmi2" "f16c" "fma")
+   endmacro()
+   macro(_x86_64_v4)
+      list(APPEND _march_flag_list "x86-64-v4")
+      _x86_64_v3()
+      list(APPEND _march_flag_list "avx512f" "avx512bw" "avx512cd" "avx512dq" "avx512vl")
+   endmacro()
 
    if(TARGET_ARCHITECTURE STREQUAL "core")
       list(APPEND _march_flag_list "core2")
@@ -412,6 +431,14 @@ Other supported values are: \"none\", \"generic\", \"core\", \"merom\" (65nm Cor
       list(APPEND _march_flag_list "barcelona")
       list(APPEND _march_flag_list "core2")
       list(APPEND _available_vector_units_list "sse" "sse2" "sse3" "sse4a")
+   elseif(TARGET_ARCHITECTURE STREQUAL "x86-64")
+      _x86_64()
+   elseif(TARGET_ARCHITECTURE STREQUAL "x86-64-v2")
+      _x86_64_v2()
+   elseif(TARGET_ARCHITECTURE STREQUAL "x86-64-v3")
+      _x86_64_v3()
+   elseif(TARGET_ARCHITECTURE STREQUAL "x86-64-v4")
+      _x86_64_v4()
    elseif(TARGET_ARCHITECTURE STREQUAL "generic")
       list(APPEND _march_flag_list "generic")
    elseif(TARGET_ARCHITECTURE STREQUAL "none")