esy resolution for GMP

esy.json-fragment

    "gmp": {
      "source": "archive:https://gmplib.org/download/gmp/gmp-6.1.2.tar.xz#9dc6981197a7d92f339192eea974f5eca48fcffe",
      "override": {
        "buildsInSource": true,
        "build": [
          "find ./ -exec touch -t 200905010101 {} +",
          "./configure --prefix=#{self.install} --host x86_64-w64-mingw32 CFLAGS=-fPIC",
          "make"
        ],
        "install": [
          "make install"
        ],
        "exportedEnv": {
          "CFLAGS": {
            "scope": "global",
            "val": "-I#{self.install / 'include'} $CFLAGS"
          },
          "LDFLAGS": {
            "scope": "global",
            "val": "-L#{self.lib} $LDFLAGS"
          }
        }
      }
    }