devel/libpeas: work around incomplete target dependency

../tests/libpeas/extension-c.c:32:10: fatal error: 'plugins/embedded/embedded-resources.h' file not found
 #include "plugins/embedded/embedded-resources.h"
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PR:		259080
Reported by:	antoine (via exp-run)
Regressed by:	https://github.com/mesonbuild/meson/commit/22c38a000673

devel/libpeas/Makefile

@@ -37,6 +37,11 @@ OPTIONS_SUB=	yes
 DOCS_BUILD_DEPENDS=	gtkdoc-scan:textproc/gtk-doc
 DOCS_MESON_TRUE=	gtk_doc
 
+pre-build:
+# XXX DISABLE_MAKE_JOBS build fails on 12.2/13.0 i386
+	${DO_MAKE_BUILD} -C ${BUILD_WRKSRC} \
+		tests/libpeas/plugins/embedded/embedded-resources.h
+
 .if ${LIBPEAS_SLAVE} == python
 USES+=		python:3.6+
 USE_PYTHON=	flavors