Merge branch 'arm_fixes' into 'master'
ARM Fixes See merge request !734 Few changes for ARM ThunderX2 and ARM-clang: Do not assume char is signed. Use int8_t for the time-bin . Improve the detection of the ARMv8.1a cycle counter assembly instruction. Fix cycle.h for ARMv8.1a. Will push upstream to FFTW. Add a synchronization point in the memswap() for clang on ARM. Do not let the autotools choose the flags for clang and GCC on ARM 8.1a. Use the native instructions. Upgrade to some of the autotools macros.