dri2: fix old memory leak during screen init with i965

[GermanAizek]

Hotfix related to issue: #1413

Changes:

• Result of dri2_probe_driver_name is saved to the temporary variable driver_name
• ds->driverNames[0] always gets this pointer
• ds->driverNames[1] gets either the string literal "va_gl" or the same pointer driver_name

[algrid]

It looks like you just introduced a temporary variable keeping the logic intact. What exactly fixes the leak there? Am I missing something?

[stefan11111]

It looks like you just introduced a temporary variable keeping the logic intact. What exactly fixes the leak there? Am I missing something?

I don't see any fix either.

The fix would be to always allocate the driverNames string on th heap and free it after it's used.

@GermanAizek I doubt these few bytes that get leaked when the screen is initialized are enough to be detected.
Are you sure that the linked issues isn't about something else?

[cepelinas9000]

@Stefan @algrid strdup in the DRI2ScreenInit leaks - something like 8 bytes per restart and contributes to noise in memleak report:

Direct leak of 48 byte(s) in 6 object(s) allocated from:
    #0 0x7ffff791c9db in strdup /usr/src/debug/sys-devel/gcc-15.2.0/gcc-15.2.0/libsanitizer/asan/asan_interceptors.cpp:593
    #1 0x555555b61e71 in dri2_probe_driver_name ../hw/xfree86/dri2/dri2.c:1477
    #2 0x555555b61e71 in DRI2ScreenInit ../hw/xfree86/dri2/dri2.c:1614
    #3 0x7ffff655bfb0 in ms_dri2_screen_init ../hw/xfree86/drivers/video/modesetting/dri2.c:1101
    #4 0x7ffff655ee37 in ScreenInit ../hw/xfree86/drivers/video/modesetting/driver.c:2122
    #5 0x5555556dcf39 in AddScreen ../dix/dispatch.c:4124
    #6 0x555555a2ca9c in InitOutput ../hw/xfree86/common/xf86Init.c:636
    #7 0x5555556eabe4 in dix_main ../dix/main.c:198
    #8 0x7ffff74783fa  (/usr/lib64/libc.so.6+0x273fa)
    #9 0x7fffffffde69  ([stack]+0x27e69)

@GermanAizek suggest to refactor to work with all names

note: i'm using nvidia modeset