Here you'll find a build script and mozconfig file for firefox-1.0.7 from the firefox tarball (not the full mozilla sources). I believe you'll find the procedure the same.
I don't mind mentioning that it cost me about 2 months of experimenting to get that to work! There are other ways to compile mozilla software,also. I found using a mozconfig file the most flexible way to produce various packages. The source tarball has been re-packed (without changes) for easier usage with Amigo PkgBuild. You can get PkgBuild here:
Since the build script uses my PkgBuild you won't see any detailed code related to temp directories or unpack, etc in the build script -just the important options which are really different from normal compiles. Note that this mozconfig will build firefox using GTK-1.2. Change
that if you like -have fun playing with the options!
Speaking of playing with the options, I've actually produced a GTK-1.2 version of the MINIMO browser -just 8MB for the whole package. That means 80% of what's best about the firefox browser
at only 20% of the size. I'm hacking around on MINIMO and TestGtkEmbed code to produce a small browser with better rendering than dillo, but still using only GTK-1.2.