Merge pull request #222 from dividiti/arm-support

Only use the "-m32" or "-m64" compiler flags on x86.

Author: Kent Knox

src/CMakeLists.txt

@@ -296,9 +296,17 @@ if(CMAKE_COMPILER_IS_GNUCXX)
     # Don't use -rpath.
     set(CMAKE_SKIP_RPATH ON CACHE BOOL "Skip RPATH" FORCE)
 
-    set(CMAKE_C_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_C_FLAGS}")
-    set(CMAKE_CXX_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_CXX_FLAGS}")
-    set(CMAKE_Fortran_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_Fortran_FLAGS}")
+    # Need to determine the target machine of the C compiler, because
+    # the '-m32' and '-m64' flags are supported on x86 but not on e.g. ARM.
+    exec_program( "${CMAKE_C_COMPILER} -dumpmachine"
+        OUTPUT_VARIABLE CMAKE_C_COMPILER_MACHINE )
+    message( STATUS "CMAKE_C_COMPILER_MACHINE: ${CMAKE_C_COMPILER_MACHINE}" )
+    # The "86" regular expression matches x86, x86_64, i686, etc.
+    if(${CMAKE_C_COMPILER_MACHINE} MATCHES "86")
+        set(CMAKE_C_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_C_FLAGS}")
+        set(CMAKE_CXX_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_CXX_FLAGS}")
+        set(CMAKE_Fortran_FLAGS "-m${TARGET_PLATFORM} ${CMAKE_Fortran_FLAGS}")
+    endif()
 
     if(TARGET_PLATFORM EQUAL 32)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-builtin")