substituting another compiler for avr-g++

I am really in the weeds here and any contribution would be gratefully accepted.

I am attempting to use the IDE with another compiler(LCC re-targeted for a 1970's microprocessor).

At the moment, I'm just replacing the avr-xxx modules in C:...\arduino-1.0.3\hardware\tools\avr\bin with stubs that invoke my compiler.

My puzzle is a discrepancy between the commands the compiler displays and the parameters my stub says it's getting. For example - the IDE displays

C:\apps\arduino-1.0.3\hardware\tools\avr\bin\avr-g++ 
-c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega644p 
-DF_CPU=1600000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=103 
-IC:\apps\arduino-1.0.3\hardware\arduino\cores\arduino -IC:\apps\arduino-1.0.3\hardware\arduino\variants\standard C:\Users\bill\AppData\Local\Temp\build2832089004955701964.tmp\Blink.cpp 
-o C:\Users\bill\AppData\Local\Temp\build2832089004955701964.tmp\Blink.cpp.o

but my stub sees

Command-line arguments:   argv[0]   C:\apps\arduino-1.0.3\hardware\tools\avr\bin\avr-g++,   
argv[1-13]=...   
argv[14]   -IC:\apps\arduino-1.0.3\hardware\arduino\cores\arduino,   
argv[15]   -IC:\apps\arduino-1.0.3\hardware\arduino\variants\standard,   
argv[16]   Blink.cpp,   argv[17]   -o,   argv[18]   Blink.cpp.o,]

i.e., the path information is missing from the input and output file names. could this be transmitted some different way like an environment variable? Seems unlikely but ...