gpm: pull upstream fix for -fno-common compiler

Fixes build failure against upstream gcc (defaults -fno-common).

pkgs/servers/gpm/default.nix

···
       url = "https://raw.githubusercontent.com/gentoo/musl/5aed405d87dfa92a5cab1596f898e9dea07169b8/sys-libs/gpm/files/gpm-1.20.7-sysmacros.patch";
       sha256 = "0lg4l9phvy2n8gy17qsn6zn0qq52vm8g01pgq5kqpr8sd3fb21c2";
     })
+    (fetchpatch {
+      # upstream build fix against -fno-common compilers like >=gcc-10
+      url = "https://github.com/telmich/gpm/commit/f04f24dd5ca5c1c13608b144ab66e2ccd47f106a.patch";
+      sha256 = "1q5hl5m61pci2f0x7r5in99rmqh328v1k0zj2693wdlafk9dabks";
+    })
   ];
   preConfigure = ''
     ./autogen.sh