Hardcoded /usr/include/tirpc path

[mboisson]

Hardcoded /usr/include/tirpc path

[jwpeterson]

That looks like a test which was specific to Fedora 28.

AS_IF([test "$enablexdr" != no],
      [
      dnl Check whether the system/compiler has xdr.h in /usr/include and glibc.
      AC_MSG_CHECKING([for built-in XDR support])
      CONFIGURE_XDR

      dnl Check for headers in /usr/include/tirpc. (Fedora 28 does this.)
      AS_IF([test "x$enablexdr" = "xno"],
            [
              AC_MSG_CHECKING([for XDR support in /usr/include/tirpc])
              old_CPPFLAGS="$CPPFLAGS"
              old_LIBS="$LIBS"
              CPPFLAGS="$CPPFLAGS -I/usr/include/tirpc"
              LIBS="$LIBS -ltirpc"

              CONFIGURE_XDR

              dnl If that worked, append the required include paths and libraries as necessary.
              AS_IF([test "x$enablexdr" = "xyes"],
                    [
                      libmesh_optional_INCLUDES="$libmesh_optional_INCLUDES -I/usr/include/tirpc"
                      libmesh_optional_LIBS="$libmesh_optional_LIBS -ltirpc"
                    ])

              dnl Reset flags after testing
              CPPFLAGS="$old_CPPFLAGS"
              LIBS="$old_LIBS"
           ])
      ])

I guess the thinking here was that the average user has no idea where the rpc and xdr headers on their system are, so we didn't make it a customizable option? I agree it would be worth adding as an expert-friendly configure flag.

[roystgnr]

The original idea was that RPC and XDR headers were standardized in the 1980s so it would be reasonable to just assume they're in the compiler's search paths already. But they never made it into POSIX so that wasn't a reasonable assumption in the end.

The second idea was that, okay, some systems move them around, but at least there's a new pseudostandard place. But that only works for users who can easily get software installed, which means it's not reasonable for all HPC systems. I've been pointing out how to manually override compiler and linker flags a couple times lately as a workaround.

And the third idea was the least reasonable of the three: "I should fix this but I'm too busy with other things and too lazy when I'm not busy". Thanks for beating me to it!

[jwpeterson]

That looks like a test which was specific to Fedora 28.

While working on #3711 I realized Ubuntu 22 (and probably previous releases) is also using /usr/include/tirpc now, so seems like there is at least some standardization around that.