When using OSX 10.6+, the --64 flag is not necessary (the 64-bit version will be built automatically), but when it is included, it causes an error:
$ sudo scons --prefix=/opt/mongo --64 --full install Install file: "build/darwin/64/client_build/libmongoclient.a" as "libmongoclient.a" Install file: "libmongoclient.a" as "/opt/mongo/lib/libmongoclient.a" scons: *** [/opt/mongo/lib/libmongoclient.a] AssertionError : Installing source ['libmongoclient.a', 'build/darwin/64/client_build/libmongoclient.a'] into target ['/opt/mongo/lib/libmongoclient.a']: target and source lists must have same length. Traceback (most recent call last): File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/scons-2.0.1/SCons/Action.py", line 1046, in execute result = self.execfunction(target=target, source=rsources, env=env) File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/scons-2.0.1/SCons/Tool/install.py", line 79, in installFunc "Installing source %s into target %s: target and source lists must have same length."%(list(map(str, source)), list(map(str, target))) AssertionError: Installing source ['libmongoclient.a', 'build/darwin/64/client_build/libmongoclient.a'] into target ['/opt/mongo/lib/libmongoclient.a']: target and source lists must have same length. scons: building terminated because of errors.
The following compiles just fine:
$ sudo scons --prefix=/opt/mongo install
(The above was done using commit 82b5219b3a2989f99bd33f3300eae22aeeac947c)