I have code that I want to compile on all unix systems, but if -m64 i available and it works, I want the configure script to use it. How do I get autoconf to check to see if -m64 works and, if so, use it?
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I have code that I want to compile on all unix systems, but if -m64 i available and it works, I want the configure script to use it. How do I get autoconf to check to see if -m64 works and, if so, use it?
my_save_cflags="$CFLAGS" CFLAGS=-m64 AC_MSG_CHECKING([whether CC supports -m64]) AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])], [AC_MSG_RESULT([yes])] [AM_CFLAGS=-m64], [AC_MSG_RESULT([no])] ) CFLAGS="$my_save_cflags" AC_SUBST([AM_CFLAGS])Using AM_CFLAGS to add -m64 to the build assumes automake
(or the use of AM_CFLAGS in your own non-automade makefiles.)