[ooc-compiler] oo2c-2.0.18 allocator problem

[Frank C. <fj...@wo...>]

I'm building VO_031223 with oo2c_32-2.0.18 on a Debian testing box. With an empty
~/VisualOberon, VisualPrefs crashes with the following output:

## 
## Runtime error in module Object at pos 11466
## Array index out of range, 100 not in 0 <= x < 100
## 
0: /usr/local/lib/liboo2c.so.0 [0x4038302b]
1: /usr/local/lib/liboo2c.so.0(_runtime_error+0x4a) [0x403830da]
2: /usr/local/lib/liboo2c.so.0 [0x40383646]
3: /usr/local/lib/liboo2c.so.0(Object__NewLatin1+0x6a) [0x4038455a]
4: /usr/local/lib/liboo2c_vo.so.0(VO_OS_X11_Display__DisplayDesc_Open+0x1377) [0x400f3c47]
5: /usr/local/lib/liboo2c_vo.so.0(VO_OS_Probe__OpenDisplay+0x204) [0x400ff544]
6: VisualPrefs [0x804c0c2]
7: VisualPrefs [0x804c522]
8: /lib/libc.so.6(__libc_start_main+0xc6) [0x404d0dc6]
9: VisualPrefs [0x804bfb1]

The problem appears to be that the 'theme' element in the DisplayPrefsDesc
object isn't being cleared when the object is allocated. Adding a statement
to VO:OS:X11:Display.Mod to explicitly assign an empty string to 'theme'
cures the problem.

This problem does not occur when VisualPrefs is compiled with
oo2c_32-2.0.17, so suspicion immediately falls on the change to the
allocator in 2.0.18 to use GC_malloc_atomic in some cases. 

'man GC_malloc_atomic' says that GC_malloc_atomic doesn't clear the
allocated memory, which is consistent with the observed behaviour. However,
the DisplayPrefsDesc object does contain pointers, so GC_malloc_atomic
shouldn't be getting called.

Frank Copeland
-- 
All a man needs out of life is a place to sit 'n' spit in the fire.