[syslinux] syslinux 3.31 will not build on RHEL3

[Tom G. Christensen]

Hi,

I've attempted to build 3.31 on RHEL3 but it fails since __DBL_MIN_EXP__ 
and __DBL_MAX_EXP__ used in com32/lib/math/strtod.c is undefined.
I added defines with the values used on RHEL4 (derived from cpp -E -dM < 
/dev/null) and the build then completes. A quick test did not reveal any 
ill effects.
Is there perhaps a better workaround for this?

Another little nit I saw was that com32/lib/MCONFIG has 
-FPNG_NO_WRITE_SUPPORTED, should this not be -DPNG_NO_WRITE_SUPPORTED?
I assume it refers to the defines in pngconf.h so to me it looks like a 
typo.

-tgc