Disable -mfpu=neon for aarch64

Disable -mfpu command line argument on aarch64, because it is not available in gcc (aarch64)

Author: hesmar

CMakeLists.txt

@@ -272,7 +272,11 @@ else()
 endif(CMAKE_SYSTEM_PROCESSOR MATCHES "x86|x86_64|AMD64|amd64|i386|i686")
 
 if(HAVE_NEON)
-  set(NEON_COMPILE_FLAGS "-mfpu=neon")
+  # -mfpu compiler option is not available for aarch64
+  # see: https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html
+  if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64.*|AARCH64.*")
+    set(NEON_COMPILE_FLAGS "-mfpu=neon")
+  endif(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "arm64|aarch64.*|AARCH64.*")
   message(STATUS "LTO build is not supported on arm/RBPi.")
   set(ENABLE_LTO FALSE)  # enable LTO cause fatal error on arm/RBPi
 endif()