Just a FYI that compiling httpd trunk (HEAD) against apr-1.7 (HEAD) and apu-1.6 (HEAD), I get no error messages about APR_OFF_T_FMT issues, so I'm not exactly sure where these are coming from for macOS
% uname -a Darwin jimsys.local 18.2.0 Darwin Kernel Version 18.2.0: Thu Dec 20 20:46:53 PST 2018; root:xnu-4903.241.1~1/RELEASE_X86_64 x86_64 % clang -v Apple LLVM version 10.0.0 (clang-1000.11.45.5) Target: x86_64-apple-darwin18.2.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin