main entry missing if crate_type = "bin" and "lib" is both given

[klutzy]

#![crate_type = "lib"]
#![crate_type = "bin"]

fn main() {
    println!("hello world");
}

error: linking with `cc` failed: exit code: 1
...
note: /usr/lib/gcc/i486-linux-gnu/4.7/../../../i386-linux-gnu/crt1.o: In function `_start':
(.text+0x18): undefined reference to `main'
collect2: error: ld returned 1 exit status

Reproduced on linux32 and win32.

[alexcrichton]

This is mildly expected, and I would likely expect a compiler error to be generated rather than attempting to continue compilation.

Codegen is tweaked slightly depending on whether you're compiling an executable or a library.

[larsbergstrom]

Aha, we've been running into this with our attempts to create an embedding version of Servo. Basically, we'd like to compile our main crate both into a binary and into a library that we can use for embedding hosts (e.g., Chromium). I guess we can do this as two steps instead.

CC @zmike