Exactly what did you download, from where, how did you run ./configure, what platform do you have... Not everyone here is mind-reader.
Just for the record: valgind-3.8.1 doesn't compile for me either (x86_64, Debian-6.0.5, gcc 4.4.5)
Code:
gcc -Wno-long-long -Wno-pointer-sign -fno-stack-protector \
-Wbad-function-cast -Wcast-qual -Wcast-align -fstrict-aliasing \
-m64 -mpreferred-stack-boundary=2 -O2 -g -Wall -Wmissing-prototypes -Wshadow -Wpointer-arith -Wstrict-prototypes -Wmissing-declarations -Wno-format-zero-length -fno-strict-aliasing -fno-builtin -fomit-frame-pointer \
-O -S -o auxprogs/genoffsets.s \
auxprogs/genoffsets.c
auxprogs/genoffsets.c:1: error: -mpreferred-stack-boundary=2 is not between 4 and 12