Makefile: allow to build executor without -static
Makefile: allow to build executor without -static

-static is not supported on some platforms

xairy/syzkaller,xairy/syzkaller,sploving/syzkaller,lorenzo-stoakes/syzkaller,dotweiba/syzkaller,google/syzkaller,sploving/syzkaller,dotweiba/syzkaller,hyz0906/syzkaller,google/syzkaller,xairy/syzkaller,sploving/syzkaller,xairy/syzkaller,lorenzo-stoakes/syzkaller,google/syzkaller,xairy/syzkaller,zoulasc/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,hyz0906/syzkaller,dotweiba/syzkaller,sploving/syzkaller,lorenzo-stoakes/syzkaller,zoulasc/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,dotweiba/syzkaller,zoulasc/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,hyz0906/syzkaller