Disable base64, fastops and libcpuid on unsupported platforms better

cmake/find/base64.cmake

-if(NOT ARCH_PPC64LE)
+if(ARCH_AMD64 OR ARCH_ARM)
     option (ENABLE_BASE64 "Enable base64" ${ENABLE_LIBRARIES})
 elseif(ENABLE_BASE64)
-    message (${RECONFIGURE_MESSAGE_LEVEL} "base64 library is not supported on PowerPC")
+    message (${RECONFIGURE_MESSAGE_LEVEL} "base64 library is only supported on x86_64 and aarch64")
 endif()
 
 if (NOT ENABLE_BASE64)

cmake/find/fastops.cmake

-if(NOT ARCH_ARM AND NOT OS_FREEBSD AND NOT OS_DARWIN AND NOT ARCH_PPC64LE)
+if(ARCH_AMD64 AND NOT OS_FREEBSD AND NOT OS_DARWIN)
     option(ENABLE_FASTOPS "Enable fast vectorized mathematical functions library by Mikhail Parakhin" ${ENABLE_LIBRARIES})
 elseif(ENABLE_FASTOPS)
-    message (${RECONFIGURE_MESSAGE_LEVEL} "Fastops library is not supported on ARM, FreeBSD and Darwin")
+    message (${RECONFIGURE_MESSAGE_LEVEL} "Fastops library is supported on x86_64 only, and not FreeBSD or Darwin")
 endif()
 
 if(NOT ENABLE_FASTOPS)

contrib/libcpuid-cmake/CMakeLists.txt

-if (NOT ARCH_ARM AND NOT ARCH_PPC64LE)
+if(ARCH_AMD64)
     option (ENABLE_CPUID "Enable libcpuid library (only internal)" ${ENABLE_LIBRARIES})
-endif()
-
-if (ARCH_ARM AND ENABLE_CPUID)
-    message (${RECONFIGURE_MESSAGE_LEVEL} "cpuid is not supported on ARM")
+elseif(ENABLE_CPUID)
+    message (${RECONFIGURE_MESSAGE_LEVEL} "libcpuid is only supported on x86_64")
     set (ENABLE_CPUID 0)
-endif ()
+endif()
 
 if (NOT ENABLE_CPUID)
     add_library (cpuid INTERFACE)