[tlbuild] Problem with program_invocation_name on Cygwin

[Ken Brown]

The latest release of Cygwin defines program_invocation_name and 
program_invocation_short_name.  This seems to conflict with something in 
the texlive sources.  As a result, the build of texlive now fails as 
follows:

gcc -DHAVE_CONFIG_H -I. -I../../../texk/xdvik -I../../../texk/xdvik/gui 
-DPS_GS -I/tmp/tl2011/source/Work/texk -I/tmp/tl2011/source/texk 
-I/tmp/tl2011/source/Work/libs/t1lib     -Wimplicit -Wreturn-type 
-Wdeclaration-after-statement -Wno-unknown-pragmas -g -O2 -MT main.o -MD 
-MP -MF .deps/main.Tpo -c -o main.o ../../../texk/xdvik/main.c
In file included from /usr/include/errno.h:9,
                  from /tmp/tl2011/source/texk/kpathsea/c-errno.h:22,
                  from /tmp/tl2011/source/texk/kpathsea/c-std.h:74,
                  from /tmp/tl2011/source/texk/kpathsea/config.h:88,
                  from ../../../texk/xdvik/xdvi.h:43,
                  from ../../../texk/xdvik/main.c:10:
/usr/include/sys/errno.h:25: error: expected '=', ',', ';', 'asm' or 
'__attribute__' before '.' token
/usr/include/sys/errno.h:26: error: expected '=', ',', ';', 'asm' or 
'__attribute__' before '.' token

Lines 25 and 26 of /usr/include/sys/errno.h are:

extern __IMPORT char *program_invocation_name;
extern __IMPORT char *program_invocation_short_name;

I've grepped the texlive sources for program_invocation_name and 
program_invocation_short_name, and I see that they are both defined as 
macros in kpathsea/types.h.  Is this the problem?

Ken