icc4 supported options.
Other options are ignored.

-C[+|-]
   -C+: Perform compile only, no link.
   -C-: Perform compile and link.  
   Default: -C-
-D<name> Define preprocessor macros to the value '1'.
-D<name>=<value> Define preprocessor macros to the value given.
-Fc[+|-]
   -Fc+: Perform syntax and semantic check only.
   Default: -Fc-
-Fe<name> Specify the name of the executable file.
   If you specify name.exe, you need not specify -Ge+ option.
   If you specify name.dll, you need not specify -Ge- option.
-Fm[+|-]
   -Fm+: Produce a linker map file.
   -Fm-: Produce no linker map file.
   Default: -Fm-
-Fm<name> Specify the name of the linker map file.
-Fo[+|-]
   -Fo+: Generate the object file.
   -Fo-: Generate no object file.
   Default: -Fo-
-Fo<dir><name> Specify the name/path of the object file.
-G3 Generate code optimized for use on an x86 processor.
-G4 Generate code optimized for use on an 80486 processor.
-G5 Generate code optimized for use on an Pentium processor.
-G6 Generate code optimized for use on an Pentium2 processor.
-Gd[+|-]
   -Gd+: Use the version of the runtime library that is dynamically linked.
   -Gd-: Use the version of the runtime library that is statically linked.  
   Default: -Gd-
-Ge[+|-]
   -Ge+: Use the version of the runtime library that assumes an EXE is being built.
   -Ge-: Use the version of the runtime library that assumes a DLL is being built.  
   Default: -Ge+
-Gf[+|-]
   -Gf+: Generate fast floating-point code.
   -Gf-: Not generate fast floating-point code.
   Default: -Gf-
-Gh[+|-]
   -Gh+: Generate profiler hooks in function prologs.
   -Gh-: Do not generate profiler hooks in function prologs.
   Default: -Gh-
-Gi[+|-]
   -Gi+: Generate fast integer code.
   -Gi-: Do not generate fast integer code.  
   Default: -Gi-
-Gl[+|-]       
   -Gl+: Enable smart linking.
   -Gl-: Disable smart linking. 
   Default: -Gl-
-Gm[+|-]
   -Gm+: Link with multithread runtime libraries.
   -Gm-: Link with singlethread runtime libraries.
   Default: -Gm+
-Gn[+|-]       
   -Gn+: Do not generate default libraries in object.
   -Gn-: Generate default libraries in object.
   Default: -Gn-
-Gp[+|-]      
   -Gp+: Generate code that allows the __parmdwords() function to work.
   -Gp-: Do not support use of the __parmdwords() function.
   Default: -Gp-
-Gr[+|-]       
   -Gr+: Allow object code to run at ring 0.
   -Gr-: Do not allow object code to run at ring 0.  
   Default: -Gr-
-Gs[+|-]       -Gs+
   -Gs+: Suppress stack probes in function prologs.
   -Gs-: Do not suppress stack probes in function prologs.
   Default: -Gs-
-Gt[+|-]
   -Gt+: Store variables so that they do not cross 64K boundaries.
   -Gt-: Store variables so that they can cross 64K boundaries.
   Default: Gt-
-Gx[+|-] 
   -Gx+: Disable the generation of C++ exception handling code.
   -Gx-: Enable the generation of C++ exception handling code.
   Default: -Gx-
-H<num> Set the maximum length of external names.
   Default: -H255
-I<path>[;<path>] Specify where to search for include files.
-J[+|-]
   -J+: Make default char type unsigned.  
   -J-: Make default char type signed.
   Default: -J+
-Mp Set the default calling convention to _Optlink. This is default.
-Ms Set the default calling convention to _System.
-Mc Set the default calling convention to __cdecl.
-Mt Set the default linkage to __stdcall.
-Nd<name> Specify the name for the default data, uninitialized data, and constant segments. 
   Default: use DATA32, BSS32 and CONST32_RO.
-Nt<name> Specify the name for the default text segment.
   Default: -NtCODE32
-Nx<name> Specify segment name for exception handling code and data.
   Default: use  EH_CODE and EH_DATA.
-O[+|-|2|3|4]
   -O-: Disable optimization of generated code.
   -O+, -O2, -O3, -O4: Enable optimization of generated code.
   Default: -O-
-Oc[+|-]      
   -Oc+: Optimize for code size rather than speed.
   -Oc-: Disable this optimization.
   Default: -Oc-
-Oi[+|-]       
   -Ot+: Turn on function inlining.
   -Ot-: Turn off function inlining.
 Default: -Ot-
-Op[+|-]      
   -Op+: Disable all stack pointer optimizations and forces the stack to be chained.
   -Op-: Enables all stack pointer optimizations and allow stack to be unchained.
   Default: -Op-
-Oq[+|-]       -Oq-
   -Oq+: Forces the stack to be chained.
   -Oq-: Allow stack to be unchained.
   Default: -Oq-
-Os[+|-]       -Os-
   -Os+: Invoke instruction scheduler.  
   -Os-: Do not invoke instruction scheduler.  
   Default: -Os-
-qalias=<val> Specifies the aliasing assertion to be applied to your compilation unit.
   val=allp,typ,addr,ansi
-qarch=<val> Specifies the architecture on which the executable program will be run.
   val=blend,x86,486,pentium,pentium2
   Default: -qarch=blend
-qbitfields=[signed|unsigned] Specifies sign of bitfields.
   Default: -qbitfields=unsigned.
-qdbgunref Generate symbol table information for unreferenced variables.
-qdbgnounref Do not generate symbol table information for unreferenced variables. This is default.
-qdigraph Allow special digraph and keyword operators.
-qnodigraph Do not allow special digraph and keyword operators. This is default.
-qignerrno Tell the optimizer that the program will never refer to or set errno.
-qignprag=<val> Ignore the aliasing pragmas disjoint and/or isolated_call.
   val=disjoint,isolated,all
-qinitauto=<val> Initialize automatic storage by the value.
   val is two digits hex
-qisolated_call=<name>[:<name>] List functions that do not change data objects at time of function call.
-qlibansi Process standard C libary names as system function.
-qnolibansi Do not process standard C libary names as system function. This is default.
-qlonglong Allow long long integers. This is default.
-qnolonglong Do not allow long long integers.
-qro Put string literals in read only area. This is default.
-qnoro Do not put string literals in read only area.
-qrtti=<val> Generate run-time type information.
   val=dynamiccast,typeinfo,all
-qnortti Do not generate run-time type information. This is default.
-qtune=<val> Specifies the architecture system for which the executable program is optimized.
   val=blend,x86,486,pentium,pentium2
   Default: -qtune=blend
-R[e|n]
   -Re: Produce code to run with a complete runtime environment.
   -Rn: Produce code to run with no runtime environment.
   Default: -Re
-Sp[1|2|4|8|16] Pack aggregate members on specified alignment.
   Default: -Sp4
-STACK=<val> Specifies the stack size. <val> can be decimal or hex (ex. 0x1000).
-Ti[+|-] 
   -Ti+: Generate debugging information.
   -Ti-: Do not generate debugging information.
   Default: -Ti-
-Tm[+|-]
   -Tm+: Generate debugging information.
   -Tm-: Do not generate debugging information.
   Default: -Tm-
-Tx[+|-]       
   -Tx+: Generate full exception register dump.
   -Tx-: Do not generate full exception register dump.
   Default: -Tx-
-U<name> Undefine user macro.
-W0 Output only severe and unrecoverable error messages generated by the compiler.
-W1 Output error, severe, and unrecoverable error messages generated by the compiler.
-W2 Output warning, error, severe and unrecoverable error messages generated by the compiler.
-W3 Output all messages generated by the compiler. This is default.
-PMTYPE=[VIO|PM] Specify OS/2 application type.
   Default: -PMTYPE=VIO
-EXEPACK=[YES|NO|1|2] Compress executable.
   Default: -EXEPACK=2
-OPTFUNC Remove unreferenced functions.      
-NOOPTFUNC Do not remove unreferenced functions. This is default.
-SHOWPROGRESS=<value> Show the progress of build by the interval of value seconds.
-CODESTORE=<codestore> Specify the code store file. The file type must be ".ics".
-NOCODESTORE Does not use code store file.
   Default: -CODESTORE=icc4.ics
   The icc4.ics is stored at the directory that TMP points.
-CLEANCODESTORE Clear the code store file.

Difference between icc4 and icc:
                icc4 icc
-G3 Means:      x86  80386
-Gm Default is: -Gm+ -Gm-