Disable strict-aliasing for gcc compiler

When strict-aliasing is enabled, gcc may generate
incorrect code for modules whose pointer variables
could point to multiple types of structure.
Eliminate warning: iss may be used uninitialized

cmpsc.c: In function 's390_compression_call':
cmpsc.c:1388: warning: 'iss[7]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[7]' was declared here
cmpsc.c:1388: warning: 'iss[6]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[6]' was declared here
cmpsc.c:1388: warning: 'iss[5]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[5]' was declared here
cmpsc.c:1388: warning: 'iss[4]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[4]' was declared here
cmpsc.c:1388: warning: 'iss[3]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[3]' was declared here
cmpsc.c:1388: warning: 'iss[2]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[2]' was declared here
cmpsc.c:1388: warning: 'iss[1]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[1]' was declared here
cmpsc.c:1388: warning: 'iss[0u]' may be used uninitialized in this function
cmpsc.c:1388: note: 'iss[0u]' was declared here
Eliminate warning: variable opts is used uninitialized
Eliminate warning: data argument not used by format string