configure: properly check if -lrt and -lm is needed

Fixes build against uClibc.

uClibc provides 2 versions of clock_gettime(), one with realtime
support and one without (this is so you can avoid linking in -lrt
unless actually needed). This means that the clock_gettime() don't
need -lrt. We still need it for timer_create() so we check for this
function in addition.

We also need check if -lm is needed for isnan().

Both -lm and -lrt are needed for libs_qga.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Luca Bruno <lucab@debian.org>
Fix generating qemu-doc.html with texinfo 5

./qemu-options.texi:1521: unknown command `list'
./qemu-options.texi:1521: table requires an argument: the formatter for @item
./qemu-options.texi:1521: warning: @table has text but no @item

CC: qemu-stable@nongnu.org
Signed-off-by: Cole Robinson <crobinso@redhat.com>
s2ecmd: Add command fork to enable/disable forking

Add command fork to enable/disable forking by using
s2e_enable_forking() and s2e_disable_forking()

Signed-off-by: Lance Chen <cyen0312@gmail.com>