GMAKE and timestamps

[Keith Knauber]

Hi, this question is related to a question posted in the April timeframe.
I'm running gmake version 3.77

My goal is to create several versions of software using the same Makefile.
Each version differs by only a handful of .o files out of hundreds.
By rebuilding only those .o files that need to be rebuilt, I save lots of
time.
So, I tried dynamically creating a .h file as part of the Makefile, and
recompiling.
Here is that portion of that makefile: 

all:    Makefile rules.hw rules.module rules.depend
        rm -f pkg_platform.h
        gmake IMAGE_FILENAME=5262 PKG_MODEM_PLATFORM=PKG_PLATFORM_5262
5262_app
        rm -f pkg_platform.h
        gmake IMAGE_FILENAME=5264 PKG_MODEM_PLATFORM=PKG_PLATFORM_5264
5264_app
        rm -f pkg_platform.h
        gmake IMAGE_FILENAME=5200 PKG_MODEM_PLATFORM=PKG_PLATFORM_5200
5200_app

LIBS=

5262_app: pkg_platform.h $(IMAGE_FILENAME).img

5264_app: pkg_platform.h $(IMAGE_FILENAME).img

5200_app: pkg_platform.h $(IMAGE_FILENAME).img


pkg_platform.h:
        echo "#define PKG_MODEM_PLATFORM $(PKG_MODEM_PLATFORM)" >
pkg_platform.h
        sleep 5



The problem is that I have to sleep for 5 seconds between each make, or else
gmake (intermittently) does not recognize that the .h has changed.

Is there a better way to accomplish this goal?
Is there a way to force a recompile of everyone who depends on
pkg_platform.h,
regardless of the file time in pkg_platform.h?

Cheers,
Keith Knauber