I'm using XCode Version 4.3.2 (4E2002) with Berkeley db-5.3.15.
I had to use following when building for Simulator because official doc doesn't seems to be updated.
DEV_iOS=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer
export SDK_iOS=${DEV_iOS}/SDKs/iPhoneSimulator5.1.sdk
export COMPILER_iOS=${DEV_iOS}/usr/bin
export CC=${COMPILER_iOS}/gcc
export CXX=${COMPILER_iOS}/g++
export LDFLAGS="-arch i686 -pipe -Os -gdwarf-2 -no-cpp-precomp -mthumb -isysroot ${SDK_iOS}"
export CFLAGS=${LDFLAGS}
export CXXFLAGS=${LDFLAGS}
export LD=${COMPILER_iOS}/ld
export CPP=${COMPILER_iOS}/cpp
export AR=${COMPILER_iOS}/ar
export AS=${COMPILER_iOS}/as
export NM=${COMPILER_iOS}/nm
export CXXCPP=${COMPILER_iOS}/cpp
export RANLIB=${COMPILER_iOS}/ranlib
../dist/configure --host=i686-apple-darwin10 --with-cryptography=no --enable-shared=no --enable-sql --prefix=/build_output_dir
make install
and following for the device.
DEV_iOS=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer
export SDK_iOS=${DEV_iOS}/SDKs/iPhoneSimulator5.1.sdk
export COMPILER_iOS=${DEV_iOS}/usr/bin
export CC=${COMPILER_iOS}/gcc
export CXX=${COMPILER_iOS}/g++
export LDFLAGS="-arch armv6 -pipe -Os -gdwarf-2 -no-cpp-precomp -mthumb -isysroot ${SDK_iOS}"
export CFLAGS=${LDFLAGS}
export CXXFLAGS=${LDFLAGS}
export LD=${COMPILER_iOS}/ld
export CPP=${COMPILER_iOS}/cpp
export AR=${COMPILER_iOS}/ar
export AS=${COMPILER_iOS}/as
export NM=${COMPILER_iOS}/nm
export CXXCPP=${COMPILER_iOS}/cpp
export RANLIB=${COMPILER_iOS}/ranlib
../dist/configure --host=arm-apple-darwin10 --with-cryptography=no --enable-shared=no --enable-sql --prefix=/build_output_dir
make install
I used lipo command to check if resulting libraries build for desired architecture.
lipo -info libdb-5.3.a
Specifying "--enable-sql" at config creates the SQL API for you, I'm using same DB wrapper I used to have for SQLite3.