You can specify command-line options by setting the value of a tool-specific environment variable:
ARMCCfor the assembler
ARMCCfor the compiler
ARMCCfor the fromelf image converter
ARMCCfor the linker.
The syntax is identical to the command-line syntax. The compilation tool reads the value of the environment variable and inserts it at the front of the command string. This means that you can override options specified in the environment variable by arguments on the command-line.