text: #!/bin/bash
  #
  # Compiler detection
  # Sets:
  #  CC, CXX, CFLAGS, CPPFLAGS, LDFLAGS, ARFLAGS, PKG_CONFIG, INSTALL, MBITS
  
  
  mkl_require host
  
  function checks {
  
      # C compiler
      mkl_meta_set "ccenv" "name" "C compiler from CC env"
      if ! mkl_command_check "ccenv" "WITH_CC" cont "$CC --version"; then
          if mkl_command_check "gcc" "WITH_GCC" cont "gcc --version"; then
              CC=gcc
          elif mkl_command_check "clang" "WITH_CLANG" cont "clang --version"; then
              CC=clang
          elif mkl_command_check "cc" "WITH_CC" fail "cc --version"; then
              CC=cc
          fi
      fi
      export CC="${CC}"
      mkl_mkvar_set CC CC "$CC"
  
      if [[ $MKL_CC_WANT_CXX == 1 ]]; then
      # C++ compiler
          mkl_meta_set "cxxenv" "name" "C++ compiler from CXX env"
          if ! mkl_command_check "cxxenv" "WITH_CXX" cont "$CXX --version" ; then
              mkl_meta_set "gxx" "name" "C++ compiler (g++)"
              mkl_meta_set "clangxx" "name" "C++ compiler (clang++)"
              mkl_meta_set "cxx" "name" "C++ compiler (c++)"
              if mkl_command_check "gxx" "WITH_GXX" cont "g++ --version"; then
                  CXX=g++
              elif mkl_command_check "clangxx" "WITH_CLANGXX" cont "clang++ --version"; then
                  CXX=clang++
              elif mkl_command_check "cxx" "WITH_CXX" fail "c++ --version"; then
                  CXX=c++
              fi
          fi
          export CXX="${CXX}"
          mkl_mkvar_set "CXX" CXX "$CXX"
      fi
  
      # Handle machine bits, if specified.
      if [[ ! -z "$MBITS" ]]; then
  	mkl_meta_set mbits_m name "mbits compiler flag (-m$MBITS)"
  	if mkl_compile_check mbits_m "" fail CC "-m$MBITS"; then
  	    mkl_mkvar_append CPPFLAGS CPPFLAGS "-m$MBITS"
  	    mkl_mkvar_append LDFLAGS LDFLAGS "-m$MBITS"
  	fi
  	if [[ -z "$ARFLAGS" && $MBITS == 64 && $MKL_DISTRO == "sunos" ]]; then
  	    # Turn on 64-bit archives on SunOS
  	    mkl_mkvar_append ARFLAGS ARFLAGS "S"
  	fi
      fi
  
      # Provide prefix and checks for various other build tools.
      local t=
      for t in LD:ld NM:nm OBJDUMP:objdump STRIP:strip LIBTOOL:libtool RANLIB:ranlib ; do
          local tenv=${t%:*}
          t=${t#*:}
  	local tval="${!tenv}"
  
          [[ -z $tval ]] && tval="$t"
  
          if mkl_prog_check "$t" "" disable "$tval" ; then
              if [[ $tval != ${!tenv} ]]; then
  		export "$tenv"="$tval"
  	    fi
              mkl_mkvar_set $tenv $tenv "$tval"
          fi
      done
  
      # Compiler and linker flags
      [[ ! -z $CFLAGS ]]   && mkl_mkvar_set "CFLAGS" "CFLAGS" "$CFLAGS"
      [[ ! -z $CPPFLAGS ]] && mkl_mkvar_set "CPPFLAGS" "CPPFLAGS" "$CPPFLAGS"
      [[ ! -z $CXXFLAGS ]] && mkl_mkvar_set "CXXFLAGS" "CXXFLAGS" "$CXXFLAGS"
      [[ ! -z $LDFLAGS ]]  && mkl_mkvar_set "LDFLAGS" "LDFLAGS" "$LDFLAGS"
      [[ ! -z $ARFLAGS ]]  && mkl_mkvar_set "ARFLAGS" "ARFLAGS" "$ARFLAGS"
  
      if [[ $MKL_NO_DEBUG_SYMBOLS != "y" ]]; then
          # Add debug symbol flag (-g)
          # OSX 10.9 requires -gstrict-dwarf for some reason.
          mkl_meta_set cc_g_dwarf name "debug symbols compiler flag (-g...)"
          if [[ $MKL_DISTRO == "osx" ]]; then
              if mkl_compile_check cc_g_dwarf "" cont CC "-gstrict-dwarf"; then
                  mkl_mkvar_append CPPFLAGS CPPFLAGS "-gstrict-dwarf"
              else
                  mkl_mkvar_append CPPFLAGS CPPFLAGS "-g"
              fi
          else
              mkl_mkvar_append CPPFLAGS CPPFLAGS "-g"
          fi
      fi
  
  
      # pkg-config
      if [ -z "$PKG_CONFIG" ]; then
          PKG_CONFIG=pkg-config
      fi
  
      if mkl_command_check "pkgconfig" "WITH_PKGCONFIG" cont "$PKG_CONFIG --version"; then
          export PKG_CONFIG
      fi
      mkl_mkvar_set "pkgconfig" PKG_CONFIG $PKG_CONFIG
  
      [[ ! -z "$append_PKG_CONFIG_PATH" ]] && mkl_env_append PKG_CONFIG_PATH "$append_PKG_CONFIG_PATH" ":"
  
      # install
      if [ -z "$INSTALL" ]; then
  	if [[ $MKL_DISTRO == "sunos" ]]; then
  	    mkl_meta_set ginstall name "GNU install"
  	    if mkl_command_check ginstall "" ignore "ginstall --version"; then
  		INSTALL=$(which ginstall)
  	    else
  		INSTALL=$(which install)
  	    fi
          else
              INSTALL=$(which install)
  	fi
      fi
  
      if mkl_command_check "install" "WITH_INSTALL" cont "$INSTALL --version"; then
          export INSTALL
      fi
      mkl_mkvar_set "install" INSTALL $INSTALL
  
  
      # Enable profiling if desired
      if [[ $WITH_PROFILING == y ]]; then
          mkl_allvar_set "" "WITH_PROFILING" "y"
          mkl_mkvar_append CPPFLAGS CPPFLAGS "-pg"
          mkl_mkvar_append LDFLAGS LDFLAGS   "-pg"
      fi
  
      # Optimization
      if [[ $WITHOUT_OPTIMIZATION == n ]]; then
          mkl_mkvar_append CPPFLAGS CPPFLAGS "-O2"
      else
          mkl_mkvar_append CPPFLAGS CPPFLAGS "-O0"
      fi
  
      # Static linking
      if [[ $WITH_STATIC_LINKING == y ]]; then
          # LDFLAGS_STATIC is the LDFLAGS needed to enable static linking
          # of sub-sequent libraries, while
          # LDFLAGS_DYNAMIC is the LDFLAGS needed to enable dynamic linking.
          if [[ $MKL_DISTRO != "osx" ]]; then
              mkl_mkvar_set staticlinking LDFLAGS_STATIC  "-Wl,-Bstatic"
              mkl_mkvar_set staticlinking LDFLAGS_DYNAMIC "-Wl,-Bdynamic"
              mkl_mkvar_set staticlinking HAS_LDFLAGS_STATIC y
          else
              # OSX linker can't enable/disable static linking so we'll
              # need to find the .a through STATIC_LIB_libname env var
              mkl_mkvar_set staticlinking HAS_LDFLAGS_STATIC n
              # libtool -static supported
              mkl_mkvar_set staticlinking HAS_LIBTOOL_STATIC y
          fi
      fi
  
      # Check for GNU ar (which has the -M option)
      mkl_meta_set "gnuar" "name" "GNU ar"
      mkl_command_check "gnuar" "HAS_GNU_AR" disable \
                            "ar -V 2>/dev/null | grep -q GNU"
  }
  
  
  mkl_option "Compiler" "env:CC" "--cc=CC" "Build using C compiler CC" "\$CC"
  mkl_option "Compiler" "env:CXX" "--cxx=CXX" "Build using C++ compiler CXX" "\$CXX"
  mkl_option "Compiler" "ARCH" "--arch=ARCH" "Build for architecture" "$(uname -m)"
  mkl_option "Compiler" "CPU" "--cpu=CPU" "Build and optimize for specific CPU" "generic"
  mkl_option "Compiler" "MBITS" "--mbits=BITS" "Machine bits (32 or 64)" ""
  
  for n in CFLAGS CPPFLAGS CXXFLAGS LDFLAGS ARFLAGS; do
      mkl_option "Compiler" "mk:$n" "--$n=$n" "Add $n flags"
  done
  
  mkl_option "Compiler" "env:append_PKG_CONFIG_PATH" "--pkg-config-path=EXTRA_PATHS" "Extra paths for pkg-config"
  
  mkl_option "Compiler" "WITH_PROFILING" "--enable-profiling" "Enable profiling"
  mkl_option "Compiler" "WITH_STATIC_LINKING" "--enable-static" "Enable static linking"
  mkl_option "Compiler" "WITHOUT_OPTIMIZATION" "--disable-optimization" "Disable optimization flag to compiler" "n"
  mkl_option "Compiler" "env:MKL_NO_DEBUG_SYMBOLS" "--disable-debug-symbols" "Disable debugging symbols" "n"
  mkl_option "Compiler" "env:MKL_WANT_WERROR" "--enable-werror" "Enable compiler warnings as errors" "n"
  mkl_option "Compiler" "WITH_STRIP" "--enable-strip" "Strip libraries when installing" "n"
  