When statically linked Abort trap: 6 (core dumped)

[Unga]

Hi all

This is FreeBSD 9.1 on i386.

My program works well without any issue when all libraries are dynamically linked.

But when some libraries are statically link and run it develops:
Abort trap: 6 (core dumped)

How I compile and link:
cc myprog.c -Wall -O \
-L. -ls1 -ls2 \
-lz -lm -lmd -lpthread \
-o myprog


libs1.a and libs2.a are static libs.

Any idea why? 


Many thanks in advance.

Regards
Unga