have_library: checking for main() in -lc... -------------------- yes

"gcc -o conftest -I. -I/home/matt/.rvm/rubies/ruby-1.8.7-p352/lib/ruby/1.8/x86_64-linux -I.    -g -O2  -fPIC   -O0 -Wall conftest.c  -L. -L/home/matt/.rvm/rubies/ruby-1.8.7-p352/lib -Wl,-R/home/matt/.rvm/rubies/ruby-1.8.7-p352/lib -L.  -rdynamic -Wl,-export-dynamic     -lruby-static -lc  -lrt -ldl -lcrypt -lm   -lc"
conftest.c: In function ‘t’:
conftest.c:3:28: warning: variable ‘p’ set but not used [-Wunused-but-set-variable]
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { void ((*volatile p)()); p = (void ((*)()))main; return 0; }
/* end */

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