meson: fix libqos linking

Add genh to the sources to avoid race conditions between QAPI
file generation and libqos compilation.

Make the name_suffix .fa for consistency with other link_whole
static libraries and to work around a Meson issue where
lots of linker flags are placed between -Wl,--start-group and
-Wl,--end-group and this breaks the fork-fuzz.ld linker script.

Reported-by: Claudio Fontana <cfontana@suse.de>
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/qtest/libqos/meson.build

@@ -1,5 +1,4 @@
-libqos = static_library('qos',
-  files('../libqtest.c',
+libqos_srcs = files('../libqtest.c',
         'qgraph.c',
         'qos_external.c',
         'pci.c',
@@ -52,6 +51,10 @@ libqos = static_library('qos',
         'arm-xilinx-zynq-a9-machine.c',
         'ppc64_pseries-machine.c',
         'x86_64_pc-machine.c',
-), build_by_default: false)
+)
+
+libqos = static_library('qos', libqos_srcs + genh,
+                        name_suffix: 'fa',
+                        build_by_default: false)
 
 qos = declare_dependency(link_whole: libqos)