UWIN - Overriding /Od with /Ox warning message?

The following warning may appear on UWIN:

$ nmake
+ cc -O -D_BLD_DLL -g -I- -D_TRACE_ -c foo.c
Command line warning D4025 : overriding '/Od' with '/Ox'

The UWIN cc wrapper translates -O to the cl.exe option -Ox which is max optimizations. The wrapper also converts -g to -Zi -Od. -Zi generates debug information and -Od disables optimizations.

When CCFLAGS+=-g is used, -g is appended to the default CCFLAGS which gives us -O -g. The UWIN cc wrapper then passes -Zi -Od -Ox to cl.exe, which gives the warning message since the two optimizer flags conflict.

If the default -O flag is removed from CCFLAGS by setting CCFLAGS=-g, then -Ox is not passed to cl.exe and no warning is generated.