Xilinx EDK : mb-gcc linker errors with C++ features

I am using Xilinx EDK 7.1.2 Build EDK_H.12.5.1+0, targeting the
Microblaze. If I define a pure virtual function in a C++ class and
declare an object of a derived class in which that function is
overridden, linker errors result for "realloc" if Library/OS parameters
STDIN and STDOUT are defined as "None", and additionally for "outbyte"
and "inbyte" if they are defined as "RS232". A transcript for the
latter case follows:

Command xbash -q -c "cd /cygdrive/c/Test/XPS/; /usr/bin/make -f
system.make program; exit;" Started...

mb-gcc -O0 C:/Test/src/main.cpp -o Test/executable.elf \
-mno-xl-soft-mul -g -I./microblaze_0/include/ -IC:/Test/src/
-L./microblaze_0/lib/ \
-xl-mode-executable \
-D__cplusplus -Weffc++ -DNDEBUG -lstdc++
/cygdrive/c/EDK/gnu/microblaze/nt/bin/../lib/gcc/microblaze/3.4.1/../../../../microblaze/lib/libstdc++.a(cp-demangle.o):
In function `d_print_resize':
/cygdrive/y/gnu_builds/halite/env/Jobs/MDT/sw/nt/gnu1/bld_mb_gcc/microblaze/libstdc++-v3/libsupc++/cp-demangle.c(.text+0x23b0):
undefined reference to `realloc'
../microblaze_0/lib//libc.a(write.o): In function `write':
write.o(.text+0x2c): undefined reference to `outbyte'
write.o(.text+0x58): undefined reference to `outbyte'
write.o(.text+0x68): undefined reference to `outbyte'
../microblaze_0/lib//libc.a(read.o): In function `read':
read.o(.text+0x3c): undefined reference to `inbyte'
collect2: ld returned 1 exit status
make: *** [Test/executable.elf] Error 1
Done.

If I supply null routines simply to satisfy the linker, I notice an
increase of 60K in code size. The virtual function definition is:

virtual void Get_String(char string[]) = 0;

If I simply change the above line to "virtual void Get_String(char
string[]) {};", no linker errors result and the program runs as
expected.

If I write code in which a (C++) exception is thrown and handled, the
same linker errors occur as listed above. The only workaround here is
to write a lot of error-handling code.

Despite the references in the error messages, my program does not call
any printing routines.

.

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