freebsd: add troubleshooting advice to use gmake instead of make for bootstrapping.

[spytheman]

GNU's make is available everywhere.

[medvednikov]

I'd rather make make work on freebsd, so that the instructions are the same for all systems.

Will test this on a freebsd VM later.

[joe-conigliaro]

There are are a lot of differences between the syntax's. However BSD make will first look for a file called BSDmakefile and gnu make will first look for a file called GNUmakefile before it looks for Makefile.

So I suggest we either:

1. Use very simple features only, which might work for both.
2. Call the BSD one BSDmakefile and leave the GNU one as Makefile
3. Call the BSD one BSDmakefile and GNU one GNUmakefile and have a Makefile.common with some common logic and include it from both other makefiles (if enough logic works for both).

@spytheman @medvednikov What are your thoughts on this?

[sunnylcw]

@joe-conigliaro Your suggestion no. 2 looks good (Call the BSD one BSDmakefile and leave the GNU one as Makefile)

[medvednikov]

Call the BSD one BSDmakefile and leave the GNU one as Makefile

Yes, I agree.

Of course ideally we would

Use very simple features only, which might work for both.

[medvednikov]

there's now a makefile for freebsd