gnulib: Use module mkstemps for RHEL 5 glibc which lacked this function.
RHEL 5: inspect: Add macro for be32toh if one is not defined in the header files.
Move Ruby-related checks from autoconf to extconf.rb; add extra check for rb_alloc_func_t

Ruby ships its own config.h which may or may not define the same
relevant constants as our autoconf-generated config.h. Instead of
trying to specify the exact path to the wanted header file we may just
as well simply use Ruby's autoconf-inspired checks and macros.
(cherry picked from commit 0ee24ccf8adb080260a5bb4260593cafe7bc016d)
EPEL 5: Remove checks which fail with ancient qemu.

Note that g->app.qemu_version and g->app.qemu_devices will both
be empty strings.
EPEL 5: Remove AS_ECHO_N for ancient autoconf.
EPEL 5: Replace macro AC_STRUCT_DIRENT_D_TYPE for ancient autoconf.
EPEL 5: Don't use C99-style variable decls in for-loop.
EPEL 5: Remove Erlang bindings.
EPEL 5: Remove GObject / GObject Introspection / GJS bindings.
EPEL 5: Remove PHP bindings.
EPEL 5: Define le64toh, le32toh if not defined.
EPEL 5: Add gnulib utimensat module.

This function is missing in RHEL 5-era kernels.
EPEL 5: Old ocamlopt didn't support debugging (-g option).
EPEL 5: Replace format6 with format4 in OCaml gettext routines.
EPEL 5: Pass --preserve-dup-deps explicitly to libtool.

See this thread:
https://lists.gnu.org/archive/html/bug-gnulib/2012-06/msg00162.html
EPEL 5: Remove id= from -drive parameter on qemu command line.
EPEL 5: Add "null vmchannel" back for qemu without virtio-serial support.
EPEL 5: Disable libvirt attach method.
EPEL 5: Fix blkid to return "LVM2_member" for PVs.

Old blkid in RHEL 5 didn't return the right thing for PVs.
EPEL 5: sparsify: Fix command line options for old qemu-img.

This didn't have -o backing_file etc.  Use old -b and -F options instead.