Log Message:
guile: fix build with GNU texinfo 6.7

GNU texinfo 6.7 fails to parse api-compound.texi because of an
unnecessary non-breaking space character (code point 160). (Whereas
GNU texinfo 6.5 succeeds there, as does the old C source version
bundled with NetBSD's userland.)

utf8 "\xA0" does not map to Unicode at ParserNonXS.pm line 1796, \ 
<FH> line 908.
Malformed UTF-8 character: \xa0 (unexpected continuation byte 0xa0, with no
preceding start byte) in pattern match (m//) at ParserNonXS.pm line 3364.
Malformed UTF-8 character (fatal) at ParserNonXS.pm line 3364.

It's simpler to just replace the byte in that source file with an ASCII
space character than attempt to fix the texinfo parsing code (and we're
in a freeze right now, too). This should fix the bulk build failures on
SmartOS and others.