Signed char hack for arm

Author: lightvector

cpp/CMakeLists.txt

@@ -485,6 +485,10 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang
   message(STATUS "Setting up build for GNU or Clang.")
   if(NOT (${CMAKE_SYSTEM_PROCESSOR} MATCHES "(arm|aarch32|aarch64)"))
     set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -mfpmath=sse")
+  else()
+    # For ARM architecture, as a hack, ensure that char is signed
+    message(STATUS "ARM architecture detected: adding -fsigned-char flag")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsigned-char")
   endif()
   if(USE_AVX2)
     set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -mavx2 -mfma")