fixed potential issues with ARM compilation under Linux

Author: svenwoop

common/cmake/gnu.cmake

@@ -8,7 +8,10 @@ MACRO(_SET_IF_EMPTY VAR VALUE)
 ENDMACRO()
 
 IF (EMBREE_ARM)
-  # No thing to declare.
+  SET(FLAGS_SSE2 "-D__SSE__ -D__SSE2__")
+  SET(FLAGS_SSE42 "-D__SSE4_2__  -D__SSE4_1__")
+  SET(FLAGS_AVX "-D__AVX__ -D__SSE4_2__  -D__SSE4_1__  -D__BMI__ -D__BMI2__ -D__LZCNT__")
+  SET(FLAGS_AVX2 "-D__AVX2__ -D__AVX__ -D__SSE4_2__  -D__SSE4_1__  -D__BMI__ -D__BMI2__ -D__LZCNT__")
 ELSE ()
   _SET_IF_EMPTY(FLAGS_SSE2  "-msse2")
   _SET_IF_EMPTY(FLAGS_SSE42 "-msse4.2")
@@ -17,7 +20,7 @@ ELSE ()
   _SET_IF_EMPTY(FLAGS_AVX512 "-mavx512f -mavx512dq -mavx512cd -mavx512bw -mavx512vl -mf16c -mavx2 -mfma -mlzcnt -mbmi -mbmi2 -mprefer-vector-width=256")
 ENDIF ()
 
-OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." OFF)
+OPTION(EMBREE_IGNORE_CMAKE_CXX_FLAGS "When enabled Embree ignores default CMAKE_CXX_FLAGS." ON)
 IF (EMBREE_IGNORE_CMAKE_CXX_FLAGS)
   SET(CMAKE_CXX_FLAGS "")
 ENDIF()