Issue
I'm trying to build OpenSSL with -Wa,--noexecstack, but can't find anywhere in its config command-line to provide this flag. I've tried to set CFLAGS, but it appears to ignore that and just use its own.
This is an automated build working off a clean copy of the OpenSSL source, so a one-time hack of the config script isn't really an option.
Is there a way to pass custom flags to OpenSSL's build process?
Solution
The config script ignores CFLAGS, but not CC. So you can specify your compiler and give it the flags at the same time:
export CC="gcc -Wall -DHELLO_WORLD"; ./config
Alternatively, since config auto detects your platform and then runs Configure with preset compiler settings, you can add the compiler flags to your platform configuration. E.g., for my mac, I see this line when I first run config:
Operating system: i386-apple-darwinDarwin Kernel Version 10.8.0: Tue Jun 7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386
Configuring for darwin-i386-cc
So if I open Configure, I can search for darwin-i386-cc and add the flags to the presets.
If you're not using a preset configuration, then you'd just pass the flags directly to Configure on the command line and it'll use them.
Answered By - indiv
