preload sets errno

[Absolucy]

Describe the bug
The library preloaded by bear sets errno to EINVAL, which causes strange errors in software that checks for errno in functions.

To Reproduce

#include <stdlib.h>
#include <errno.h>
#include <string.h>

int main()
{
	printf("error %i: %s\n", errno, strerror(errno));
	return 0;
}

$ bear -- ./a.out
error 22: Invalid argument

Expected behavior

$ ./a.out 
error 0: Success

Environment:

• OS name: Linux
• OS version: Arch Linux
• OS architecture: x86_64
• Bear version: 3.0.19
• Bear install method: Arch Linux repos

Additional context
N/A, bug is completely unrelated to build systems, and can be reliably reproduced on a basic 5-line executable.

Before you send...

• Have you read the README.md file or man bear?: Yes
• Have you looked what other open issues Bear has?: Yes
• Are you sure that the build works without Bear?: Yes

[rizsotto]

thanks @Absolucy !