Error:
When specifying "-separate-debug-info" on OS X builds, configure fails due to the missing variable QMAKE_OBJCOPY.
Unfortunately, one cannot easily set this variable to "QMAKE_OBJCOPY = objcopy" like for the Linux builds as objcopy is not available on OS X.
There are workarounds available which use a ported version of the Unix/Linux objcopy on OS X.
However, I am not an OS X expert and others certainly know how to fix this properly.

Output log:
./configure -v \
-platform macx-clang \
-opensource \
-confirm-license \
-dont-process \
-shared \
-debug-and-release \
-strip \
-force-debug-info \
-separate-debug-info \
-no-framework \
-nomake examples \
-nomake tests \
-no-rpath \
-no-icu \
-qt-sql-sqlite \
-system-zlib \
-qt-libpng \
-qt-libjpeg \
-opengl \
-no-cups \
-no-sql-db2 \
-no-sql-ibase \
-no-sql-mysql \
-no-sql-oci \
-no-sql-odbc \
-no-sql-psql \
-no-sql-sqlite2 \
-no-sql-tds \
-no-libudev \
-no-c++11

This is the Qt Open Source Edition.

You are licensed to use this software under the terms of
the Lesser GNU General Public License (LGPL) versions 2.1.
You are also licensed to use this software under the terms of
the GNU General Public License (GPL) versions 3.

You have already accepted the terms of the Open Source license.

Precompiled-headers support enabled.
Separate debug info check skipped, QMAKE_OBJCOPY is unset.
Separate debug info support disabled.
ERROR: -separate-debug-info was requested but this binutils does not support it.
Re-run configure with -v for more information
make[1]: *** [configure] Error 1
make: *** [QtBase] Error 2