[CMake] test files generated by CheckIncludeFile are not ansi conform

[Michael Biebl]

The template files for CheckIncludeFile are not ansi conform, this
means running with "CFLAGS=-Werror -Wstrict-prototypes" produces
failing tests.

The template file CheckIncludeFile.c.in and the one for cxx should
correctly read

#include <${CHECK_INCLUDE_FILE_VAR}>

int main(int argc, char *argv[])
{
  return 0;
}


Cheers,
Michael