Fixes a regression introduced in a3ed69b694
where dmeventd.static fails to link against libm and breaks "lvm2-static".
* gnu/packages/patches/lvm2-static-link.patch: Patch make.tmpl.in.
* gnu/packages/patches/lvm2-static-link.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/linux.scm (lvm2)[source](patches): New field.
(lvm2-static): New variable.