meson: add modules infrastructure

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/undefsym.sh

@@ -0,0 +1,20 @@
+#! /usr/bin/env bash
+
+# Before a shared module's DSO is produced, a static library is built for it
+# and passed to this script.  The script generates -Wl,-u options to force
+# the inclusion of symbol from libqemuutil.a if the shared modules need them,
+# This is necessary because the modules may use functions not needed by the
+# executable itself, which would cause the function to not be linked in.
+# Then the DSO loading would fail because of the missing symbol.
+
+if test $# -le 2; then
+  exit 0
+fi
+
+NM=$1
+staticlib=$2
+shift 2
+# Find symbols defined in static libraries and undefined in shared modules
+comm -12 \
+  <( $NM -P -g $staticlib | awk '$2!="U"{print "-Wl,-u," $1}' | sort -u) \
+  <( $NM -P -g "$@" | awk '$2=="U"{print "-Wl,-u," $1}' | sort -u)