The compiler wrappers (mpicc, mpic++, etc.) in Open MPI are C++ programs that read in text configuration files found in <install dir>/share/openmpi (on Unix system) and probably in <install dir>\share\openmpi on Windows. These files are called <wrapper name>-wrapper-data.txt where <wrapper name> is the name of the compiler wrapper. For example for mpicc the wrapper confiration file is called mpicc-wrapper-data.txt. Inside you'd find something similar to:
...
preprocessor_flags=-I/opt/MPI/openmpi-1.6.1/linux/intel/include ...
compiler_flags=-fexceptions -pthread -I${prefix}/lib/lib32 ...
linker_flags= -L/opt/lsf/8.0/linux2.6-glibc2.3-x86/lib ...
libs=-lmpi -losmcomp -lrdmacm -libverbs ...
...
Modify these to match your compiler flags.