sys_unix.cpp: avoid namespace collision of file_handle in fcntl-linux.h

This broke the build:

    sys_unix.cpp:73:8: error: redefinition of ‘struct file_handle’
     struct file_handle {
	    ^
    In file included from /usr/include/bits/fcntl.h:61:0,
		     from /usr/include/fcntl.h:35,
		     from sysdeps.h:61,
		     from sys_unix.cpp:21:
    /usr/include/bits/fcntl-linux.h:311:8: error: previous definition of ‘struct file_handle’
     struct file_handle
	    ^
    sys_unix.cpp: In function ‘void SysMediaArrived(const char*, int)’:
    sys_unix.cpp:211:11: error: ‘struct file_handle’ has no member named ‘is_cdrom’
       if (fh->is_cdrom && type == MEDIA_CD) {
	       ^
    sys_unix.cpp:214:9: error: ‘struct file_handle’ has no member named ‘is_media_present’
	 fh->is_media_present = true;

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
ppc-dyngen-ops: eliminate dyngen_barriers in do_lmw and do_stmw

These barriers, when present, caused GCC to do something funny with the
function exit point:

    00000000000027c1 <_Z12op_lmw_T0_imv>:
        27c1:       b8 00 00 00 00          mov    $0x0,%eax
        27c6:       48 c7 44 24 f8 00 00    movq   $0x0,-0x8(%rsp)
        27cd:       00 00
        27cf:       89 d9                   mov    %ebx,%ecx
        27d1:       83 f8 1f                cmp    $0x1f,%eax
        27d4:       48 89 ef                mov    %rbp,%rdi
        27d7:       76 0f                   jbe    27e8 <_Z12op_lmw_T0_imv+0x27>
        27d9:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
        27e0:       c3                      retq   <------------------------
        27e1:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
        27e8:       67 8b 11                mov    (%ecx),%edx
        27eb:       0f ca                   bswap  %edx
        27ed:       48 63 f0                movslq %eax,%rsi
        27f0:       83 c0 01                add    $0x1,%eax
        27f3:       83 c1 04                add    $0x4,%ecx
        27f6:       83 f8 20                cmp    $0x20,%eax
        27f9:       89 54 b7 10             mov    %edx,0x10(%rdi,%rsi,4)
        27fd:       75 e9                   jne    27e8 <_Z12op_lmw_T0_imv+0x27>
        27ff:       eb df                   jmp    27e0 <_Z12op_lmw_T0_imv+0x1f>

Instead of being placed at the end of the instruction sequence, it was placed
in the middle, causing dyngen to spaz out a bit:

    ./dyngen -o ppc-dyngen-ops.hpp obj/ppc-dyngen-ops.o
    dyngen: ret or jmp expected at the end of op_lmw_T0_im

Removing the barriers causes GCC to emit a more logical code sequence:

    00000000000027c1 <_Z12op_lmw_T0_imv>:
        27c1:       b8 00 00 00 00          mov    $0x0,%eax
        27c6:       48 c7 44 24 f8 00 00    movq   $0x0,-0x8(%rsp)
        27cd:       00 00
        27cf:       89 d9                   mov    %ebx,%ecx
        27d1:       83 f8 1f                cmp    $0x1f,%eax
        27d4:       48 89 ef                mov    %rbp,%rdi
        27d7:       77 1e                   ja     27f7 <_Z12op_lmw_T0_imv+0x36>
        27d9:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
        27e0:       67 8b 11                mov    (%ecx),%edx
        27e3:       0f ca                   bswap  %edx
        27e5:       48 63 f0                movslq %eax,%rsi
        27e8:       83 c0 01                add    $0x1,%eax
        27eb:       83 c1 04                add    $0x4,%ecx
        27ee:       83 f8 20                cmp    $0x20,%eax
        27f1:       89 54 b7 10             mov    %edx,0x10(%rdi,%rsi,4)
        27f5:       75 e9                   jne    27e0 <_Z12op_lmw_T0_imv+0x1f>
        27f7:       f3 c3                   repz retq   <-------------------

Ideally dyngen should be able to handle both cases, but that would involve
patching the generated code a bit to relocate the ret and such. For now, let's
just prevent GCC from being dumb.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
main_unix: use '1' instead of non-existent 'TRUE' macro

main_unix.cpp: In function ‘int main(int, char**)’:
main_unix.cpp:401:45: error: ‘TRUE’ was not declared in this scope
  setenv("SDL_VIDEO_ALLOW_SCREENSAVER", "1", TRUE);
                                             ^

Signed-off-by: Steven Noonan <steven@uplinklabs.net>