Undefined "___divmodsi4" linking Monotouch project with static library in release mode - xamarin.ios

Question

I have a Monotouch project linked to a static library containing C++ modules.
Monotouch version: 3.0.3.5
XCode version: 4.4.1
C/C++ Compiler: Apple LLVM 4.0
When building the project in debug mode for iOS simulator and iOS device everything is OK -
application is linked and runs.
However when building the release configuration for iOS device the following error appears:
Undefined symbols for architecture armv7: "___divmodsi4"
The following line from the static library code somehow causes the trouble:
int number_of_buckets = num_samples / window_samples_step;
If this line is modified as follows the problem disappears:
int number_of_buckets = (int)((float)num_samples / (float)window_samples_step);
Do you have any ideas how to fix the problem without the above modification?
Thanks,
Ury.

Answer 1

This occurs near the end of the build and generally depends on it's original parameters. Try to compare your options between your Release and Debug builds and check that:
you are using the same Additional mtouch arguments on both configuration;
you are using the same compiler, Mono AOT versus LLVM compilers, on both configuration;
you are using the same architecture, ARMv6 versus ARMv7, on both configuration.
Otherwise attach (e.g. preferable to a bug report or pastebin) the full build log (from the Build Output of MonoDevelop's Error Pad) for both Debug and Release builds.
To be more helpful add "-v -v -v" to the Additional mtouch arguments before re-building. This will augment the verbosity (details) about each steps.

Answer 2

You need to set the app's Deployment Target (in the project's options, Build / iPhone Application page) to at least 5.0.