Warnings in AIX

Dear experts,

please help in this regard,

when i am trying to compile some files for 64 bit in AIX, iam getting this warning

"/usr/include/alloca.h", line 34.9: 1540-1401 (I) An unknown "pragma __alloca" is specified.

how to solve this warning , what is the significance of this please inform,
please reply.

please reply.