[PATCH 1/3] extconf.rb: avoid RDoc errors during gem install

[Eric Wong <e@80x24.org>]

RDoc doesn't seem to like <<'' (blank line) as a heredoc
terminator.  That said, RDoc scanning extconf.rb during "gem install"
is unexpected and make no sense to me.  Normal `rdoc' invocations
seem to ignore extconf.rb.
---
 ext/mwrap/extconf.rb | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/ext/mwrap/extconf.rb b/ext/mwrap/extconf.rb
index 512ab82..1828407 100644
--- a/ext/mwrap/extconf.rb
+++ b/ext/mwrap/extconf.rb
@@ -11,15 +11,15 @@ have_library 'dl'
 have_library 'c'
 have_library 'execinfo' # FreeBSD
 
-if try_link(<<'')
+if try_link(<<EOC)
 int main(void) { return __builtin_add_overflow_p(0,0,(int)1); }
-
+EOC
   $defs << '-DHAVE_BUILTIN_ADD_OVERFLOW_P'
 end
 
-if try_link(<<'')
+if try_link(<<EOC)
 int main(int a) { return __builtin_add_overflow(0,0,&a); }
-
+EOC
   $defs << '-DHAVE_BUILTIN_ADD_OVERFLOW_P'
 else
   abort 'missing __builtin_add_overflow'