we really need to static-link the libs on linux

[TurkeyMan]

From one of my travis-ci builds

Creating GNU Makefile...
dist/bin/premake5: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.16' not found (required by dist/bin/premake5)

The premake binary expects to dynamic link to whatever version of the .so was on the machine that built the binary... we either need to explicitly be less fussy with the version number (ie, only specify major version), or in this case, just static link.

I might make a patch if I get a spare couple of hours to run the tests on a few machines.