icc warnings on my_bitmap

From ICC

mysys/my_bitmap.cc(32): warning #191: type qualifier is meaningless on cast type
    unsigned char const mask= static_cast<unsigned char const>((~((1 << used) - 1)) & 255);
                                          ^

mysys/my_bitmap.cc(32): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char const mask= static_cast<unsigned char const>((~((1 << used) - 1)) & 255);
                              ^

mysys/my_bitmap.cc(90): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char bit= static_cast<unsigned char>(1 << ((bitPos) & 7));
                       ^

mysys/my_bitmap.cc(91): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char res= static_cast<unsigned char>((*value) & bit);
                       ^

mysys/my_bitmap.cc(92): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    *value= static_cast<unsigned char>(*value | bit);
            ^

mysys/my_bitmap.cc(101): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char bit= static_cast<unsigned char>(1 << ((bitPos) & 7));
                       ^

mysys/my_bitmap.cc(102): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char res= static_cast<unsigned char>((*byte) & bit);
                       ^

mysys/my_bitmap.cc(103): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
libtool: compile: /opt/intel/Compiler/11.1/059/bin/intel64/icpc -gcc-name=/usr/bin/gcc-4.2 -gxx-name=/usr/bin/g++-4.2 -DHAVE_CONFIG_H -I. -I. -g -pthread -pipe -xHOST -O3 -no-prec-div -w1 -Wall -Wcheck -Wformat -Wp64 -Woverloaded-virtual -Wcast-qual -diag-disable 981 -std=gnu++98 -MT mysys/my_init.lo -MD -MP -MF mysys/.deps/my_init.Tpo -c mysys/my_init.cc -o mysys/my_init.o
    *byte= static_cast<unsigned char>(*byte & ~bit);
           ^

mysys/my_bitmap.cc(136): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
      *m++= static_cast<unsigned char>((1 << prefix_bits)-1);
            ^

mysys/my_bitmap.cc(287): remark #2259: non-pointer conversion from "int" to "unsigned char" may lose significant bits
    unsigned char use_byte= static_cast<unsigned char>(use_bit ? 0xff : 0);
                            ^