Remove -Wdeclaration-after-statement from CFLAGS

The warnings are pointless and clutter output.

Author: Uoti Urpala

configure

@@ -7608,7 +7608,6 @@ cat > $TMPC << EOF
 int main(void) { return 0; }
 EOF
 if test "$cc_vendor" = "gnu" ; then
-  cc_check -Wdeclaration-after-statement && CFLAGS="-Wdeclaration-after-statement $CFLAGS"
   cc_check -Wno-pointer-sign && CFLAGS="-Wno-pointer-sign $CFLAGS"
   cc_check -Wdisabled-optimization && CFLAGS="-Wdisabled-optimization $CFLAGS"
 fi