meson: link libm

On some platforms libm (needed for the pow() function) isn't being
linked in somehow. This patch adds the necessary bits to assure that
it's linked in when necessary.

Suggested-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
(cherry picked from commit 20a62b42ec001310a6329d7ee2021f0737d534ef)

meson.build

@@ -1176,6 +1176,9 @@ endif
 libxml_version = '2.9.1'
 libxml_dep = dependency('libxml-2.0', version: '>=' + libxml_version)
 
+cc = meson.get_compiler('c')
+m_dep = cc.find_library('m', required : false)
+
 use_macvtap = false
 if not get_option('macvtap').disabled()
   if (cc.has_header_symbol('linux/if_link.h', 'MACVLAN_MODE_BRIDGE') and

src/util/meson.build

@@ -188,6 +188,7 @@ virt_util_lib = static_library(
     devmapper_dep,
     gnutls_dep,
     libnl_dep,
+    m_dep,
     numactl_dep,
     secdriver_dep,
     src_dep,